diff --git a/bin/core/imag-edit/src/main.rs b/bin/core/imag-edit/src/main.rs
index 4b6387d9..46c4c3f9 100644
--- a/bin/core/imag-edit/src/main.rs
+++ b/bin/core/imag-edit/src/main.rs
@@ -89,7 +89,7 @@ fn main() {
     let edit_header = rt.cli().is_present("edit-header");
     let edit_header_only = rt.cli().is_present("edit-header-only");
 
-    StoreIdIterator::new(Box::new(sids.into_iter()))
+    StoreIdIterator::new(Box::new(sids.into_iter().map(Ok)))
         .into_get_iter(rt.store())
         .trace_unwrap_exit(1)
         .map(|o| o.unwrap_or_else(|| {
diff --git a/bin/core/imag-ids/src/main.rs b/bin/core/imag-ids/src/main.rs
index 08beb465..240a03ea 100644
--- a/bin/core/imag-ids/src/main.rs
+++ b/bin/core/imag-ids/src/main.rs
@@ -45,6 +45,7 @@ use filters::filter::Filter;
 
 use libimagrt::setup::generate_runtime_setup;
 use libimagerror::trace::MapErrTrace;
+use libimagerror::iter::TraceIterator;
 use libimagerror::exit::ExitUnwrap;
 use libimagerror::io::ToExitCode;
 use libimagstore::storeid::StoreId;
@@ -86,6 +87,7 @@ fn main() {
     rt.store()
         .entries()
         .map_err_trace_exit_unwrap(1)
+        .trace_unwrap_exit(1)
         .filter(|id| collection_filter.filter(id))
         .map(|id| if print_storepath {
             id
diff --git a/bin/core/imag-link/src/main.rs b/bin/core/imag-link/src/main.rs
index 4dd8e0de..46ce39e9 100644
--- a/bin/core/imag-link/src/main.rs
+++ b/bin/core/imag-link/src/main.rs
@@ -54,7 +54,6 @@ extern crate libimagutil;
 
 use std::io::Write;
 use std::path::PathBuf;
-use std::process::exit;
 
 use libimagentrylink::external::ExternalLinker;
 use libimagentrylink::internal::InternalLinker;
@@ -255,12 +254,11 @@ fn unlink(rt: &Runtime) {
         .map(PathBuf::from)
         .collect::<Vec<PathBuf>>().into_iter() // for lifetime inference
         .map(StoreId::new_baseless)
-        .unwrap_with(|e| { trace_error(&e); exit(1) })
         .into_get_iter(rt.store())
-        .unwrap_with(|e| { trace_error(&e); exit(1) })
-        .filter_map(|e| e)
+        .trace_unwrap_exit(1)
+        .filter_map(|x| x)
         .map(|mut entry| entry.unlink(rt.store()))
-        .unwrap_with(|e| { trace_error(&e); exit(1) })
+        .trace_unwrap_exit(1)
         .collect::<Vec<_>>();
 }
 
diff --git a/bin/core/imag-mv/src/main.rs b/bin/core/imag-mv/src/main.rs
index fbb5021e..aeac022b 100644
--- a/bin/core/imag-mv/src/main.rs
+++ b/bin/core/imag-mv/src/main.rs
@@ -49,9 +49,11 @@ use std::path::PathBuf;
 
 use libimagrt::setup::generate_runtime_setup;
 use libimagerror::trace::MapErrTrace;
+use libimagerror::iter::TraceIterator;
 use libimagstore::storeid::StoreId;
 use libimagstore::store::Store;
 use libimagstore::store::FileLockEntry;
+use libimagstore::error::StoreError;
 use libimagentrylink::internal::InternalLinker;
 use libimagstore::iter::get::StoreIdGetIteratorExtension;
 
@@ -91,11 +93,11 @@ fn main() {
             })
             .get_internal_links()
             .map_err_trace_exit_unwrap(1)
-            .map(|link| link.get_store_id().clone())
+            .map(|link| Ok(link.get_store_id().clone()) as Result<_, StoreError>)
             .into_get_iter(rt.store())
+            .trace_unwrap_exit(1)
             .map(|e| {
-                e.map_err_trace_exit_unwrap(1)
-                .unwrap_or_else(|| {
+                e.unwrap_or_else(|| {
                     error!("Linked entry does not exist");
                     exit(1)
                 })
diff --git a/bin/core/imag-view/src/main.rs b/bin/core/imag-view/src/main.rs
index 5cafb007..bef7e2bc 100644
--- a/bin/core/imag-view/src/main.rs
+++ b/bin/core/imag-view/src/main.rs
@@ -68,10 +68,10 @@ use libimagentryview::builtin::md::MarkdownViewer;
 use libimagentryview::viewer::Viewer;
 use libimagentryview::error::ViewError as VE;
 use libimagstore::storeid::IntoStoreId;
+use libimagstore::storeid::StoreIdIterator;
 use libimagstore::error::StoreError;
 use libimagstore::iter::get::StoreIdGetIteratorExtension;
 use libimagstore::store::FileLockEntry;
-use libimagstore::storeid::StoreId;
 
 mod ui;
 use ui::build_ui;
@@ -89,11 +89,10 @@ fn main() {
 
     if rt.cli().is_present("in") {
         let files = entry_ids
-            .into_iter()
             .into_get_iter(rt.store())
+            .trace_unwrap_exit(1)
             .map(|e| {
-                 e.map_err_trace_exit_unwrap(1)
-                     .ok_or_else(|| String::from("Entry not found"))
+                 e.ok_or_else(|| String::from("Entry not found"))
                      .map_err(StoreError::from)
                      .map_err_trace_exit_unwrap(1)
             })
@@ -175,7 +174,6 @@ fn main() {
         drop(files);
     } else {
         let iter = entry_ids
-            .into_iter()
             .into_get_iter(rt.store())
             .map(|e| {
                  e.map_err_trace_exit_unwrap(1)
@@ -249,13 +247,13 @@ fn main() {
     }
 }
 
-fn entry_ids(rt: &Runtime) -> Vec<StoreId> {
+fn entry_ids(rt: &Runtime) -> StoreIdIterator {
     match rt.cli().values_of("id") {
-        Some(pathes) => pathes
-            .map(PathBuf::from)
-            .map(PathBuf::into_storeid)
-            .trace_unwrap_exit(1)
-            .collect(),
+        Some(p) => {
+            let pathes : Vec<String> = p.map(String::from).collect();
+            let iter  = pathes.into_iter().map(PathBuf::from).map(PathBuf::into_storeid);
+            StoreIdIterator::new(Box::new(iter))
+        },
 
         None => if rt.cli().is_present("entries-from-stdin") {
             let stdin = rt.stdin().unwrap_or_else(|| {
@@ -269,11 +267,10 @@ fn entry_ids(rt: &Runtime) -> Vec<StoreId> {
                 ::std::process::exit(1)
             });
 
-            buf.lines()
-                .map(PathBuf::from)
-                .map(PathBuf::into_storeid)
-                .trace_unwrap_exit(1)
-                .collect()
+            let lines : Vec<String> = buf.lines().map(String::from).collect();
+            let iter  = lines.into_iter().map(PathBuf::from).map(PathBuf::into_storeid);
+
+            StoreIdIterator::new(Box::new(iter))
         } else {
             error!("Something weird happened. I was not able to find the path of the entries to edit");
             ::std::process::exit(1)
diff --git a/bin/domain/imag-diary/src/list.rs b/bin/domain/imag-diary/src/list.rs
index 55ab2740..a40cd0ff 100644
--- a/bin/domain/imag-diary/src/list.rs
+++ b/bin/domain/imag-diary/src/list.rs
@@ -23,6 +23,7 @@ use libimagdiary::diary::Diary;
 use libimagrt::runtime::Runtime;
 use libimagutil::warn_exit::warn_exit;
 use libimagerror::trace::MapErrTrace;
+use libimagerror::iter::TraceIterator;
 use libimagerror::io::ToExitCode;
 use libimagerror::exit::ExitUnwrap;
 use libimagutil::debug_result::*;
@@ -40,6 +41,7 @@ pub fn list(rt: &Runtime) {
     let mut ids = Diary::entries(rt.store(), &diaryname)
         .map_dbg_str("Ok")
         .map_err_trace_exit_unwrap(1)
+        .trace_unwrap_exit(1)
         .map(|id| DiaryId::from_storeid(&id))
         .collect::<Result<Vec<_>>>()
         .map_err_trace_exit_unwrap(1);
diff --git a/bin/domain/imag-diary/src/view.rs b/bin/domain/imag-diary/src/view.rs
index 7e48fd90..763d2456 100644
--- a/bin/domain/imag-diary/src/view.rs
+++ b/bin/domain/imag-diary/src/view.rs
@@ -21,6 +21,7 @@ use libimagdiary::diary::Diary;
 use libimagdiary::viewer::DiaryViewer as DV;
 use libimagrt::runtime::Runtime;
 use libimagerror::trace::MapErrTrace;
+use libimagerror::iter::TraceIterator;
 use libimagutil::warn_exit::warn_exit;
 use libimagstore::iter::get::StoreIdGetIteratorExtension;
 use libimagentryview::viewer::Viewer;
@@ -34,7 +35,7 @@ pub fn view(rt: &Runtime) {
     let entries = Diary::entries(rt.store(), &diaryname)
         .map_err_trace_exit_unwrap(1)
         .into_get_iter(rt.store())
-        .filter_map(Result::ok)
+        .trace_unwrap_exit(1)
         .map(|e| e.unwrap_or_else(|| {
             error!("Failed to fetch entry");
             ::std::process::exit(1)
diff --git a/bin/domain/imag-habit/src/main.rs b/bin/domain/imag-habit/src/main.rs
index 61b69bd6..218a0d67 100644
--- a/bin/domain/imag-habit/src/main.rs
+++ b/bin/domain/imag-habit/src/main.rs
@@ -57,6 +57,7 @@ use prettytable::row::Row;
 use libimagrt::runtime::Runtime;
 use libimagrt::setup::generate_runtime_setup;
 use libimagerror::trace::{MapErrTrace, trace_error};
+use libimagerror::iter::TraceIterator;
 use libimagerror::exit::ExitUnwrap;
 use libimagerror::io::ToExitCode;
 use libimaghabit::store::HabitStore;
@@ -167,6 +168,7 @@ fn delete(rt: &Runtime) {
         .store()
         .all_habit_templates()
         .map_err_trace_exit_unwrap(1)
+        .trace_unwrap_exit(1)
         .map(|sid| (sid.clone(), rt.store().get(sid).map_err_trace_exit_unwrap(1))) // get the FileLockEntry
         .filter(|&(_, ref habit)| match habit { // filter for name of habit == name we look for
             &Some(ref h) => h.habit_name().map_err_trace_exit_unwrap(1) == name,
@@ -198,6 +200,7 @@ fn delete(rt: &Runtime) {
                 fle
                     .linked_instances()
                     .map_err_trace_exit_unwrap(1)
+                    .trace_unwrap_exit(1)
                     .filter_map(get_instance)
                     .filter(has_template_name)
                     .map(instance_location)
@@ -249,6 +252,7 @@ fn today(rt: &Runtime, future: bool) {
             .store()
             .all_habit_templates()
             .map_err_trace_exit_unwrap(1)
+            .trace_unwrap_exit(1)
             .filter_map(|id| match rt.store().get(id.clone()) {
                 Ok(Some(h)) => Some(h),
                 Ok(None) => {
@@ -396,6 +400,7 @@ fn list(rt: &Runtime) {
         .store()
         .all_habit_templates()
         .map_err_trace_exit_unwrap(1)
+        .trace_unwrap_exit(1)
         .filter_map(|id| match rt.store().get(id.clone()) {
             Ok(Some(h)) => Some(h),
             Ok(None) => {
@@ -451,6 +456,7 @@ fn show(rt: &Runtime) {
         .store()
         .all_habit_templates()
         .map_err_trace_exit_unwrap(1)
+        .trace_unwrap_exit(1)
         .filter_map(|id| get_from_store(rt.store(), id))
         .filter(|h| h.habit_name().map(|n| name == n).map_err_trace_exit_unwrap(1))
         .enumerate()
@@ -474,6 +480,7 @@ fn show(rt: &Runtime) {
             let _ = habit
                 .linked_instances()
                 .map_err_trace_exit_unwrap(1)
+                .trace_unwrap_exit(1)
                 .filter_map(|instance_id| {
                     debug!("Getting: {:?}", instance_id);
                     rt.store().get(instance_id).map_err_trace_exit_unwrap(1)
@@ -505,6 +512,7 @@ fn done(rt: &Runtime) {
             .store()
             .all_habit_templates()
             .map_err_trace_exit_unwrap(1)
+            .trace_unwrap_exit(1)
             .filter_map(|id| get_from_store(rt.store(), id))
             .filter(|h| {
                 let due = h.next_instance_date().map_err_trace_exit_unwrap(1);
diff --git a/bin/domain/imag-mail/src/main.rs b/bin/domain/imag-mail/src/main.rs
index e010c46e..f36e01c4 100644
--- a/bin/domain/imag-mail/src/main.rs
+++ b/bin/domain/imag-mail/src/main.rs
@@ -43,6 +43,7 @@ extern crate libimagutil;
 use std::io::Write;
 
 use libimagerror::trace::{MapErrTrace, trace_error};
+use libimagerror::iter::TraceIterator;
 use libimagerror::exit::ExitUnwrap;
 use libimagerror::io::ToExitCode;
 use libimagmail::mail::Mail;
@@ -143,6 +144,7 @@ fn list(rt: &Runtime) {
     let _ = rt.store()
         .entries()
         .map_err_trace_exit_unwrap(1)
+        .trace_unwrap_exit(1)
         .filter(|id| id.is_in_collection(&["mail"]))
         .filter_map(|id| {
             rt.store()
diff --git a/bin/domain/imag-todo/src/main.rs b/bin/domain/imag-todo/src/main.rs
index cf1d4ccb..622bcce2 100644
--- a/bin/domain/imag-todo/src/main.rs
+++ b/bin/domain/imag-todo/src/main.rs
@@ -50,6 +50,7 @@ use libimagrt::runtime::Runtime;
 use libimagrt::setup::generate_runtime_setup;
 use libimagtodo::taskstore::TaskStore;
 use libimagerror::trace::{MapErrTrace, trace_error};
+use libimagerror::iter::TraceIterator;
 use libimagerror::exit::ExitUnwrap;
 use libimagerror::io::ToExitCode;
 
@@ -124,7 +125,7 @@ fn list(rt: &Runtime) {
     let res = rt.store().all_tasks() // get all tasks
         .map(|iter| { // and if this succeeded
             // filter out the ones were we can read the uuid
-            let uuids : Vec<_> = iter.filter_map(|storeid| {
+            let uuids : Vec<_> = iter.trace_unwrap_exit(1).filter_map(|storeid| {
                 match rt.store().retrieve(storeid) {
                     Ok(fle) => {
                         match fle.get_header().read_string("todo.uuid") {
diff --git a/bin/domain/imag-wiki/src/main.rs b/bin/domain/imag-wiki/src/main.rs
index 5c393bca..6e586009 100644
--- a/bin/domain/imag-wiki/src/main.rs
+++ b/bin/domain/imag-wiki/src/main.rs
@@ -34,6 +34,7 @@ use std::io::Write;
 
 use libimagrt::runtime::Runtime;
 use libimagrt::setup::generate_runtime_setup;
+use libimagerror::iter::TraceIterator;
 use libimagerror::trace::MapErrTrace;
 use libimagerror::exit::ExitUnwrap;
 use libimagerror::io::ToExitCode;
@@ -90,6 +91,7 @@ fn ids(rt: &Runtime, wiki_name: &str) {
         })
         .all_ids()
         .map_err_trace_exit_unwrap(1)
+        .trace_unwrap_exit(1)
         .for_each(|id| {
             let _ = writeln!(outlock, "{}{}", prefix, id)
                 .to_exit_code()
diff --git a/lib/core/libimagrt/src/runtime.rs b/lib/core/libimagrt/src/runtime.rs
index 8766cda7..093bd3cc 100644
--- a/lib/core/libimagrt/src/runtime.rs
+++ b/lib/core/libimagrt/src/runtime.rs
@@ -22,6 +22,7 @@ use std::process::Command;
 use std::env;
 use std::process::exit;
 use std::io::Stdin;
+use std::sync::Arc;
 
 pub use clap::App;
 use clap::AppSettings;
@@ -132,7 +133,7 @@ impl<'a> Runtime<'a> {
         let store_result = if cli_app.use_inmemory_fs() {
             Store::new_with_backend(storepath,
                                     &config,
-                                    Box::new(InMemoryFileAbstraction::default()))
+                                    Arc::new(InMemoryFileAbstraction::default()))
         } else {
             Store::new(storepath, &config)
         };
diff --git a/lib/core/libimagstore/src/file_abstraction/fs.rs b/lib/core/libimagstore/src/file_abstraction/fs.rs
index a41a2239..8ee7ee9d 100644
--- a/lib/core/libimagstore/src/file_abstraction/fs.rs
+++ b/lib/core/libimagstore/src/file_abstraction/fs.rs
@@ -168,20 +168,15 @@ impl FileAbstraction for FSFileAbstraction {
     fn pathes_recursively(&self, basepath: PathBuf) -> Result<PathIterator, SE> {
         use walkdir::WalkDir;
 
-        let i : Result<Vec<PathBuf>, SE> = WalkDir::new(basepath)
+        let i = WalkDir::new(basepath)
             .min_depth(1)
+            .max_open(100)
             .into_iter()
             .map(|r| {
-                r.map(|e| PathBuf::from(e.path()))
-                    .chain_err(|| SE::from_kind(SEK::FileError))
-            })
-            .fold(Ok(vec![]), |acc, e| {
-                acc.and_then(move |mut a| {
-                    a.push(e?);
-                    Ok(a)
-                })
+                r.map(|e| PathBuf::from(e.path())).chain_err(|| SE::from_kind(SEK::FileError))
             });
-        Ok(PathIterator::new(Box::new(i?.into_iter())))
+
+        Ok(PathIterator::new(Box::new(i)))
     }
 }
 
diff --git a/lib/core/libimagstore/src/file_abstraction/inmemory.rs b/lib/core/libimagstore/src/file_abstraction/inmemory.rs
index efe0c4f4..495286fd 100644
--- a/lib/core/libimagstore/src/file_abstraction/inmemory.rs
+++ b/lib/core/libimagstore/src/file_abstraction/inmemory.rs
@@ -183,15 +183,15 @@ impl FileAbstraction for InMemoryFileAbstraction {
 
     fn pathes_recursively(&self, _basepath: PathBuf) -> Result<PathIterator, SE> {
         debug!("Getting all pathes");
-        let keys : Vec<PathBuf> = self
+        let keys : Vec<Result<PathBuf, SE>> = self
             .backend()
             .lock()
             .map_err(|_| SE::from_kind(SEK::FileError))?
             .get_mut()
             .keys()
             .map(PathBuf::from)
-            .collect();
-        // we collect here as this happens only in tests and in memory anyways, so no problem
+            .map(Ok)
+            .collect(); // we have to collect() because of the lock() above.
 
         Ok(PathIterator::new(Box::new(keys.into_iter())))
     }
diff --git a/lib/core/libimagstore/src/file_abstraction/iter.rs b/lib/core/libimagstore/src/file_abstraction/iter.rs
index ca2862b3..dea30a5e 100644
--- a/lib/core/libimagstore/src/file_abstraction/iter.rs
+++ b/lib/core/libimagstore/src/file_abstraction/iter.rs
@@ -18,20 +18,31 @@
 //
 
 use std::path::PathBuf;
+use std::sync::Arc;
+
+use error::Result;
+use storeid::StoreId;
+use file_abstraction::FileAbstraction;
 
 /// A wrapper for an iterator over `PathBuf`s
-pub struct PathIterator(Box<Iterator<Item = PathBuf>>);
+pub struct PathIterator(Box<Iterator<Item = Result<PathBuf>>>);
 
 impl PathIterator {
 
-    pub fn new(iter: Box<Iterator<Item = PathBuf>>) -> PathIterator {
+    pub fn new(iter: Box<Iterator<Item = Result<PathBuf>>>) -> PathIterator {
         PathIterator(iter)
     }
 
+    pub fn store_id_constructing(self, storepath: PathBuf, backend: Arc<FileAbstraction>)
+        -> StoreIdConstructingIterator
+    {
+        StoreIdConstructingIterator(self, storepath, backend)
+    }
+
 }
 
 impl Iterator for PathIterator {
-    type Item = PathBuf;
+    type Item = Result<PathBuf>;
 
     fn next(&mut self) -> Option<Self::Item> {
         self.0.next()
@@ -39,3 +50,29 @@ impl Iterator for PathIterator {
 
 }
 
+
+/// Helper type for constructing StoreIds from a PathIterator.
+///
+/// Automatically ignores non-files.
+pub struct StoreIdConstructingIterator(PathIterator, PathBuf, Arc<FileAbstraction>);
+
+impl Iterator for StoreIdConstructingIterator {
+    type Item = Result<StoreId>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        while let Some(next) = self.0.next() {
+            match next {
+                Err(e)  => return Some(Err(e)),
+                Ok(next) => match self.2.exists(&next) {
+                    Err(e)    => return Some(Err(e)),
+                    Ok(true)  => return Some(StoreId::from_full_path(&self.1, next)),
+                    Ok(false) => { continue },
+                }
+            }
+        }
+
+        None
+    }
+
+}
+
diff --git a/lib/core/libimagstore/src/file_abstraction/mod.rs b/lib/core/libimagstore/src/file_abstraction/mod.rs
index 893b8ca2..a3172735 100644
--- a/lib/core/libimagstore/src/file_abstraction/mod.rs
+++ b/lib/core/libimagstore/src/file_abstraction/mod.rs
@@ -27,7 +27,7 @@ use storeid::StoreId;
 
 mod fs;
 mod inmemory;
-mod iter;
+pub(crate) mod iter;
 
 pub use self::fs::FSFileAbstraction;
 pub use self::fs::FSFileAbstractionInstance;
diff --git a/lib/core/libimagstore/src/iter.rs b/lib/core/libimagstore/src/iter.rs
index 0171a93b..0e066b09 100644
--- a/lib/core/libimagstore/src/iter.rs
+++ b/lib/core/libimagstore/src/iter.rs
@@ -17,111 +17,7 @@
 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 //
 
-macro_rules! mk_iterator {
-    {
-        modname   = $modname:ident,
-        itername  = $itername:ident,
-        iteryield = $yield:ty,
-        extname   = $extname:ident,
-        extfnname = $extfnname:ident,
-        fun       = $fun:expr
-    } => {
-        use storeid::StoreId;
-        #[allow(unused_imports)]
-        use store::FileLockEntry;
-        use store::Store;
-        use error::Result;
-
-        pub struct $itername<'a>(Box<Iterator<Item = StoreId> + 'a>, &'a Store);
-
-        impl<'a> $itername<'a> {
-            pub fn new(inner: Box<Iterator<Item = StoreId> + 'a>, store: &'a Store) -> Self {
-                $itername(inner, store)
-            }
-        }
-
-        impl<'a> Iterator for $itername<'a> {
-            type Item = Result<$yield>;
-
-            fn next(&mut self) -> Option<Self::Item> {
-                self.0.next().map(|id| $fun(id, self.1))
-            }
-        }
-
-        pub trait $extname<'a> {
-            fn $extfnname(self, store: &'a Store) -> $itername<'a>;
-        }
-
-        impl<'a, I> $extname<'a> for I
-            where I: Iterator<Item = StoreId> + 'a
-        {
-            fn $extfnname(self, store: &'a Store) -> $itername<'a> {
-                $itername(Box::new(self), store)
-            }
-        }
-    }
-}
-
-use error::StoreError;
-
-pub enum ExtensionError<E> {
-    Forwarded(E),
-    StoreError(StoreError)
-}
-
 macro_rules! mk_iterator_mod {
-    {
-        modname        = $modname:ident,
-        itername       = $itername:ident,
-        iteryield      = $yield:ty,
-        extname        = $extname:ident,
-        extfnname      = $extfnname:ident,
-        fun            = $fun:expr,
-        resultitername = $resultitername:ident,
-        resultextname  = $resultextname:ident
-    } => {
-        pub mod $modname {
-            mk_iterator! {
-                modname   = $modname,
-                itername  = $itername,
-                iteryield = $yield,
-                extname   = $extname,
-                extfnname = $extfnname,
-                fun       = $fun
-            }
-
-            use std::result::Result as RResult;
-
-            pub struct $resultitername<'a, I>(I, &'a Store);
-
-            impl<'a, I, E> Iterator for $resultitername<'a, I>
-                where I: Iterator<Item = RResult<StoreId, E>>
-            {
-                type Item = RResult<$yield, $crate::iter::ExtensionError<E>>;
-
-                fn next(&mut self) -> Option<Self::Item> {
-                    match self.0.next() {
-                        Some(Ok(sid)) => Some($fun(sid, self.1).map_err($crate::iter::ExtensionError::StoreError)),
-                        Some(Err(e))  => Some(Err($crate::iter::ExtensionError::Forwarded(e))),
-                        None => None,
-                    }
-                }
-            }
-
-            pub trait $resultextname<'a> : Iterator {
-                fn $extfnname(self, store: &'a Store) -> $resultitername<'a, Self>
-                    where Self: Sized
-                {
-                    $resultitername(self, store)
-                }
-            }
-
-            impl<'a, I> $resultextname<'a> for I
-                where I: Iterator
-            { /* empty */ }
-        }
-    };
-
     {
         modname   = $modname:ident,
         itername  = $itername:ident,
@@ -131,13 +27,47 @@ macro_rules! mk_iterator_mod {
         fun       = $fun:expr
     } => {
         pub mod $modname {
-            mk_iterator! {
-                modname   = $modname,
-                itername  = $itername,
-                iteryield = $yield,
-                extname   = $extname,
-                extfnname = $extfnname,
-                fun       = $fun
+            use storeid::StoreId;
+            #[allow(unused_imports)]
+            use store::FileLockEntry;
+            use store::Store;
+            use error::StoreError;
+            use std::result::Result as RResult;
+
+            pub struct $itername<'a, E>(Box<Iterator<Item = RResult<StoreId, E>> + 'a>, &'a Store)
+                where E: From<StoreError>;
+
+            impl<'a, E> $itername<'a, E>
+                where E: From<StoreError>
+            {
+                pub fn new(inner: Box<Iterator<Item = RResult<StoreId, E>> + 'a>, store: &'a Store) -> Self {
+                    $itername(inner, store)
+                }
+            }
+
+            impl<'a, E> Iterator for $itername<'a, E>
+                where E: From<StoreError>
+            {
+                type Item = RResult<$yield, E>;
+
+                fn next(&mut self) -> Option<Self::Item> {
+                    self.0.next().map(|id| $fun(id?, self.1).map_err(E::from))
+                }
+            }
+
+            pub trait $extname<'a, E>
+                where E: From<StoreError>
+            {
+                fn $extfnname(self, store: &'a Store) -> $itername<'a, E>;
+            }
+
+            impl<'a, I, E> $extname<'a, E> for I
+                where I: Iterator<Item = RResult<StoreId, E>> + 'a,
+                      E: From<StoreError>
+            {
+                fn $extfnname(self, store: &'a Store) -> $itername<'a, E> {
+                    $itername(Box::new(self), store)
+                }
             }
         }
     }
@@ -149,9 +79,7 @@ mk_iterator_mod! {
     iteryield = FileLockEntry<'a>,
     extname   = StoreIdCreateIteratorExtension,
     extfnname = into_create_iter,
-    fun       = |id: StoreId, store: &'a Store| store.create(id),
-    resultitername = StoreCreateResultIterator,
-    resultextname  = StoreIdCreateResultIteratorExtension
+    fun       = |id: StoreId, store: &'a Store| store.create(id)
 }
 
 mk_iterator_mod! {
@@ -160,9 +88,7 @@ mk_iterator_mod! {
     iteryield = (),
     extname   = StoreIdDeleteIteratorExtension,
     extfnname = into_delete_iter,
-    fun       = |id: StoreId, store: &'a Store| store.delete(id),
-    resultitername = StoreDeleteResultIterator,
-    resultextname  = StoreIdDeleteResultIteratorExtension
+    fun       = |id: StoreId, store: &'a Store| store.delete(id)
 }
 
 mk_iterator_mod! {
@@ -171,9 +97,7 @@ mk_iterator_mod! {
     iteryield = Option<FileLockEntry<'a>>,
     extname   = StoreIdGetIteratorExtension,
     extfnname = into_get_iter,
-    fun       = |id: StoreId, store: &'a Store| store.get(id),
-    resultitername = StoreGetResultIterator,
-    resultextname  = StoreIdGetResultIteratorExtension
+    fun       = |id: StoreId, store: &'a Store| store.get(id)
 }
 
 mk_iterator_mod! {
@@ -182,9 +106,7 @@ mk_iterator_mod! {
     iteryield = FileLockEntry<'a>,
     extname   = StoreIdRetrieveIteratorExtension,
     extfnname = into_retrieve_iter,
-    fun       = |id: StoreId, store: &'a Store| store.retrieve(id),
-    resultitername = StoreRetrieveResultIterator,
-    resultextname  = StoreIdRetrieveResultIteratorExtension
+    fun       = |id: StoreId, store: &'a Store| store.retrieve(id)
 }
 
 #[cfg(test)]
diff --git a/lib/core/libimagstore/src/store.rs b/lib/core/libimagstore/src/store.rs
index 7edf3f05..44afbea6 100644
--- a/lib/core/libimagstore/src/store.rs
+++ b/lib/core/libimagstore/src/store.rs
@@ -137,7 +137,7 @@ impl Iterator for Walk {
 
 impl StoreEntry {
 
-    fn new(id: StoreId, backend: &Box<FileAbstraction>) -> Result<StoreEntry> {
+    fn new(id: StoreId, backend: &Arc<FileAbstraction>) -> Result<StoreEntry> {
         let pb = id.clone().into_pathbuf()?;
 
         #[cfg(feature = "fs-lock")]
@@ -214,7 +214,7 @@ pub struct Store {
     /// The backend to use
     ///
     /// This provides the filesystem-operation functions (or pretends to)
-    backend: Box<FileAbstraction>,
+    backend: Arc<FileAbstraction>,
 }
 
 impl Store {
@@ -235,7 +235,7 @@ impl Store {
     /// - On success: Store object
     ///
     pub fn new(location: PathBuf, store_config: &Option<Value>) -> Result<Store> {
-        let backend = Box::new(FSFileAbstraction::default());
+        let backend = Arc::new(FSFileAbstraction::default());
         Store::new_with_backend(location, store_config, backend)
     }
 
@@ -245,7 +245,7 @@ impl Store {
     /// Do not use directly, only for testing purposes.
     pub fn new_with_backend(location: PathBuf,
                             store_config: &Option<Value>,
-                            backend: Box<FileAbstraction>) -> Result<Store> {
+                            backend: Arc<FileAbstraction>) -> Result<Store> {
         use configuration::*;
 
         debug!("Building new Store object");
@@ -279,33 +279,6 @@ impl Store {
         Ok(store)
     }
 
-    /// Reset the backend of the store during runtime
-    ///
-    /// # Warning
-    ///
-    /// This is dangerous!
-    /// You should not be able to do that in application code, only the libimagrt should be used to
-    /// do this via safe and careful wrapper functions!
-    ///
-    /// If you are able to do this without using `libimagrt`, please file an issue report.
-    ///
-    /// # Purpose
-    ///
-    /// With the I/O backend of the store, the store is able to pipe itself out via (for example)
-    /// JSON. But because we need a functionality where we load contents from the filesystem and
-    /// then pipe it to stdout, we need to be able to replace the backend during runtime.
-    ///
-    /// This also applies the other way round: If we get the store from stdin and have to persist it
-    /// to stdout, we need to be able to replace the in-memory backend with the real filesystem
-    /// backend.
-    ///
-    pub fn reset_backend(&mut self, mut backend: Box<FileAbstraction>) -> Result<()> {
-        self.backend
-            .drain()
-            .and_then(|drain| backend.fill(drain))
-            .map(|_| self.backend = backend)
-    }
-
     /// Creates the Entry at the given location (inside the entry)
     ///
     /// # Return value
@@ -741,25 +714,12 @@ impl Store {
     }
 
     /// Get _all_ entries in the store (by id as iterator)
-    pub fn entries<'a>(&'a self) -> Result<StoreIdIteratorWithStore<'a>> {
+    pub fn entries(&self) -> Result<StoreIdIteratorWithStore> {
         self.backend
             .pathes_recursively(self.path().clone())
-            .and_then(|iter| {
-                let mut elems = vec![];
-                for element in iter {
-                    let is_file = {
-                        let mut base = self.path().clone();
-                        base.push(element.clone());
-                        self.backend.is_file(&base)?
-                    };
-
-                    if is_file {
-                        let sid = StoreId::from_full_path(self.path(), element)?;
-                        elems.push(sid);
-                    }
-                }
-                Ok(StoreIdIteratorWithStore::new(Box::new(elems.into_iter()), self))
-            })
+            .map(|i| i.store_id_constructing(self.path().clone(), self.backend.clone()))
+            .map(Box::new)
+            .map(|it| StoreIdIteratorWithStore::new(it, self))
     }
 
     /// Gets the path where this store is on the disk
@@ -1215,12 +1175,13 @@ Hai
 #[cfg(test)]
 mod store_tests {
     use std::path::PathBuf;
+    use std::sync::Arc;
 
     use super::Store;
     use file_abstraction::InMemoryFileAbstraction;
 
     pub fn get_store() -> Store {
-        let backend = Box::new(InMemoryFileAbstraction::default());
+        let backend = Arc::new(InMemoryFileAbstraction::default());
         Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
     }
 
@@ -1400,50 +1361,5 @@ mod store_tests {
         }
     }
 
-    #[test]
-    fn test_swap_backend_during_runtime() {
-        use file_abstraction::InMemoryFileAbstraction;
-
-        let mut store = {
-            let backend = InMemoryFileAbstraction::default();
-            let backend = Box::new(backend);
-
-            Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
-        };
-
-        for n in 1..100 {
-            let s = format!("test-{}", n);
-            let entry = store.create(PathBuf::from(s.clone())).unwrap();
-            assert!(entry.verify().is_ok());
-            let loc = entry.get_location().clone().into_pathbuf().unwrap();
-            assert!(loc.starts_with("/"));
-            assert!(loc.ends_with(s));
-        }
-
-        {
-            let other_backend = InMemoryFileAbstraction::default();
-            let other_backend = Box::new(other_backend);
-
-            assert!(store.reset_backend(other_backend).is_ok())
-        }
-
-        for n in 1..100 {
-            let s = format!("test-{}", n);
-            let entry = store.get(PathBuf::from(s.clone()));
-
-            assert!(entry.is_ok());
-            let entry = entry.unwrap();
-
-            assert!(entry.is_some());
-            let entry = entry.unwrap();
-
-            assert!(entry.verify().is_ok());
-
-            let loc = entry.get_location().clone().into_pathbuf().unwrap();
-            assert!(loc.starts_with("/"));
-            assert!(loc.ends_with(s));
-        }
-    }
-
 }
 
diff --git a/lib/core/libimagstore/src/storeid.rs b/lib/core/libimagstore/src/storeid.rs
index 2bcd9ba7..3d639797 100644
--- a/lib/core/libimagstore/src/storeid.rs
+++ b/lib/core/libimagstore/src/storeid.rs
@@ -241,7 +241,7 @@ macro_rules! module_entry_path_mod {
 }
 
 pub struct StoreIdIterator {
-    iter: Box<Iterator<Item = StoreId>>,
+    iter: Box<Iterator<Item = Result<StoreId>>>,
 }
 
 impl Debug for StoreIdIterator {
@@ -254,16 +254,16 @@ impl Debug for StoreIdIterator {
 
 impl StoreIdIterator {
 
-    pub fn new(iter: Box<Iterator<Item = StoreId>>) -> StoreIdIterator {
+    pub fn new(iter: Box<Iterator<Item = Result<StoreId>>>) -> StoreIdIterator {
         StoreIdIterator { iter }
     }
 
 }
 
 impl Iterator for StoreIdIterator {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
-    fn next(&mut self) -> Option<StoreId> {
+    fn next(&mut self) -> Option<Self::Item> {
         self.iter.next()
     }
 
@@ -280,16 +280,18 @@ impl<'a> Deref for StoreIdIteratorWithStore<'a> {
 }
 
 impl<'a> Iterator for StoreIdIteratorWithStore<'a> {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
-    fn next(&mut self) -> Option<StoreId> {
+    fn next(&mut self) -> Option<Self::Item> {
         self.0.next()
     }
 }
 
+use error::StoreError;
+
 impl<'a> StoreIdIteratorWithStore<'a> {
 
-    pub fn new(iter: Box<Iterator<Item = StoreId>>, store: &'a Store) -> Self {
+    pub fn new(iter: Box<Iterator<Item = Result<StoreId>>>, store: &'a Store) -> Self {
         StoreIdIteratorWithStore(StoreIdIterator::new(iter), store)
     }
 
@@ -300,7 +302,7 @@ impl<'a> StoreIdIteratorWithStore<'a> {
     /// Transform the iterator into a StoreCreateIterator
     ///
     /// This immitates the API from `libimagstore::iter`.
-    pub fn into_create_iter(self) -> StoreCreateIterator<'a> {
+    pub fn into_create_iter(self) -> StoreCreateIterator<'a, StoreError> {
         StoreCreateIterator::new(Box::new(self.0), self.1)
     }
 
@@ -308,7 +310,7 @@ impl<'a> StoreIdIteratorWithStore<'a> {
     ///
     ///
     /// This immitates the API from `libimagstore::iter`.
-    pub fn into_delete_iter(self) -> StoreDeleteIterator<'a> {
+    pub fn into_delete_iter(self) -> StoreDeleteIterator<'a, StoreError> {
         StoreDeleteIterator::new(Box::new(self.0), self.1)
     }
 
@@ -316,7 +318,7 @@ impl<'a> StoreIdIteratorWithStore<'a> {
     ///
     ///
     /// This immitates the API from `libimagstore::iter`.
-    pub fn into_get_iter(self) -> StoreGetIterator<'a> {
+    pub fn into_get_iter(self) -> StoreGetIterator<'a, StoreError> {
         StoreGetIterator::new(Box::new(self.0), self.1)
     }
 
@@ -324,7 +326,7 @@ impl<'a> StoreIdIteratorWithStore<'a> {
     ///
     ///
     /// This immitates the API from `libimagstore::iter`.
-    pub fn into_retrieve_iter(self) -> StoreRetrieveIterator<'a> {
+    pub fn into_retrieve_iter(self) -> StoreRetrieveIterator<'a, StoreError> {
         StoreRetrieveIterator::new(Box::new(self.0), self.1)
     }
 
diff --git a/lib/domain/libimagcontact/src/iter.rs b/lib/domain/libimagcontact/src/iter.rs
index 1f99c873..48f0f403 100644
--- a/lib/domain/libimagcontact/src/iter.rs
+++ b/lib/domain/libimagcontact/src/iter.rs
@@ -43,8 +43,9 @@ impl<'a> Iterator for ContactIter<'a> {
     fn next(&mut self) -> Option<Self::Item> {
         loop {
             match self.0.next() {
-                None      => return None,
-                Some(sid) => match self.1.get(sid.clone()).map_err(From::from) {
+                None          => return None,
+                Some(Err(e))  => return Some(Err(e).map_err(CE::from)),
+                Some(Ok(sid)) => match self.1.get(sid.clone()).map_err(From::from) {
                     Err(e)          => return Some(Err(e)),
                     Ok(None)        => return Some(Err(CE::from_kind(CEK::EntryNotFound(sid)))),
                     Ok(Some(entry)) => match entry.is_contact().map_err(From::from) {
diff --git a/lib/domain/libimagcontact/src/store.rs b/lib/domain/libimagcontact/src/store.rs
index 88856b70..e2b9aea4 100644
--- a/lib/domain/libimagcontact/src/store.rs
+++ b/lib/domain/libimagcontact/src/store.rs
@@ -81,7 +81,10 @@ impl<'a> ContactStore<'a> for Store {
         let iter = self
             .entries()?
             .without_store()
-            .filter(|id| id.is_in_collection(&["contact"]));
+            .filter(|id| match *id {
+                Ok(ref id) => id.is_in_collection(&["contact"]),
+                Err(_) => true,
+            });
 
         Ok(StoreIdIterator::new(Box::new(iter)))
     }
diff --git a/lib/domain/libimagdiary/src/diary.rs b/lib/domain/libimagdiary/src/diary.rs
index 15ee28ba..ea4b2491 100644
--- a/lib/domain/libimagdiary/src/diary.rs
+++ b/lib/domain/libimagdiary/src/diary.rs
@@ -94,13 +94,27 @@ impl Diary for Store {
             .chain_err(|| DEK::StoreReadError)
     }
 
+    /// get the id of the youngest entry
+    ///
+    /// TODO: We collect internally here. We shouldn't do that. Solution unclear.
     fn get_youngest_entry_id(&self, diary_name: &str) -> Option<Result<DiaryId>> {
+        use error::DiaryError as DE;
+
         match Diary::entries(self, diary_name) {
             Err(e) => Some(Err(e)),
             Ok(entries) => {
-                entries
-                    .map(|e| DiaryId::from_storeid(&e))
-                    .sorted_by(|a, b| {
+                let mut sorted_entries = vec![];
+
+                for entry in entries {
+                    let entry = match entry {
+                        Ok(e) => DiaryId::from_storeid(&e),
+                        Err(e) => return Some(Err(e).map_err(DE::from)),
+                    };
+
+                    sorted_entries.push(entry);
+                }
+
+                sorted_entries.into_iter().sorted_by(|a, b| {
                         match (a, b) {
                             (&Ok(ref a), &Ok(ref b)) => {
                                 let a : NaiveDateTime = a.clone().into();
diff --git a/lib/domain/libimagdiary/src/iter.rs b/lib/domain/libimagdiary/src/iter.rs
index 09f9114e..6ebc5230 100644
--- a/lib/domain/libimagdiary/src/iter.rs
+++ b/lib/domain/libimagdiary/src/iter.rs
@@ -103,16 +103,17 @@ impl Filter<StoreId> for DiaryEntryIterator {
 }
 
 impl Iterator for DiaryEntryIterator {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
     fn next(&mut self) -> Option<Self::Item> {
         loop {
             match self.iter.next() {
-                None    => return None,
-                Some(s) => {
+                None         => return None,
+                Some(Err(e)) => return Some(Err(e).map_err(DE::from)),
+                Some(Ok(s))  => {
                     debug!("Next element: {:?}", s);
                     if Filter::filter(self, &s) {
-                        return Some(s)
+                        return Some(Ok(s))
                     } else {
                         continue
                     }
@@ -141,16 +142,19 @@ impl Iterator for DiaryNameIterator {
 
     fn next(&mut self) -> Option<Self::Item> {
         while let Some(next) = self.0.next() {
-            if next.is_in_collection(&["diary"]) {
-                return Some(next
-                    .to_str()
-                    .chain_err(|| DEK::DiaryNameFindingError)
-                    .and_then(|s| {
-                        s.split("diary/")
-                            .nth(1)
-                            .and_then(|n| n.split("/").nth(0).map(String::from))
-                            .ok_or(DE::from_kind(DEK::DiaryNameFindingError))
-                    }))
+            match next {
+                Err(e) => return Some(Err(e).map_err(DE::from)),
+                Ok(next) => if next.is_in_collection(&["diary"]) {
+                    return Some(next
+                        .to_str()
+                        .chain_err(|| DEK::DiaryNameFindingError)
+                        .and_then(|s| {
+                            s.split("diary/")
+                                .nth(1)
+                                .and_then(|n| n.split("/").nth(0).map(String::from))
+                                .ok_or(DE::from_kind(DEK::DiaryNameFindingError))
+                        }));
+                },
             }
         }
 
diff --git a/lib/domain/libimaghabit/src/habit.rs b/lib/domain/libimaghabit/src/habit.rs
index 36c9dcc0..cd53c290 100644
--- a/lib/domain/libimaghabit/src/habit.rs
+++ b/lib/domain/libimaghabit/src/habit.rs
@@ -131,7 +131,8 @@ impl HabitTemplate for Entry {
         let iter = self
             .get_internal_links()?
             .map(|link| link.get_store_id().clone())
-            .filter(IsHabitCheck::is_habit_instance);
+            .filter(IsHabitCheck::is_habit_instance)
+            .map(Ok);
 
         let sidi = StoreIdIterator::new(Box::new(iter));
         Ok(HabitInstanceStoreIdIterator::new(sidi))
diff --git a/lib/domain/libimaghabit/src/iter.rs b/lib/domain/libimaghabit/src/iter.rs
index fa64f1ae..6a1af765 100644
--- a/lib/domain/libimaghabit/src/iter.rs
+++ b/lib/domain/libimaghabit/src/iter.rs
@@ -22,16 +22,21 @@ use libimagstore::storeid::StoreIdIteratorWithStore;
 use libimagstore::storeid::StoreId;
 
 use util::IsHabitCheck;
+use error::Result;
+use error::HabitError as HE;
 
 pub struct HabitTemplateStoreIdIterator(StoreIdIterator);
 
 impl Iterator for HabitTemplateStoreIdIterator {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
     fn next(&mut self) -> Option<Self::Item> {
         while let Some(n) = self.0.next() {
-            if n.is_habit_template() {
-                return Some(n)
+            match n {
+                Ok(n) => if n.is_habit_template() {
+                    return Some(Ok(n))
+                },
+                Err(e) => return Some(Err(e).map_err(HE::from)),
             }
         }
         None
@@ -59,12 +64,15 @@ impl HabitInstanceStoreIdIterator {
 }
 
 impl Iterator for HabitInstanceStoreIdIterator {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
     fn next(&mut self) -> Option<Self::Item> {
         while let Some(n) = self.0.next() {
-            if n.is_habit_instance() {
-                return Some(n)
+            match n {
+                Ok(n) => if n.is_habit_instance() {
+                    return Some(Ok(n));
+                },
+                Err(e) => return Some(Err(e).map_err(HE::from)),
             }
         }
         None
diff --git a/lib/domain/libimagnotes/src/iter.rs b/lib/domain/libimagnotes/src/iter.rs
index 263506c7..98adbbd9 100644
--- a/lib/domain/libimagnotes/src/iter.rs
+++ b/lib/domain/libimagnotes/src/iter.rs
@@ -21,6 +21,8 @@ use libimagstore::storeid::StoreId;
 use libimagstore::storeid::StoreIdIterator;
 
 use notestoreid::*;
+use error::Result;
+use error::NoteError as NE;
 
 #[derive(Debug)]
 pub struct NoteIterator(StoreIdIterator);
@@ -34,12 +36,15 @@ impl NoteIterator {
 }
 
 impl Iterator for NoteIterator {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
     fn next(&mut self) -> Option<Self::Item> {
         while let Some(n) = self.0.next() {
-            if n.is_note_id() {
-                return Some(n);
+            match n {
+                Ok(n) => if n.is_note_id() {
+                    return Some(Ok(n));
+                },
+                Err(e) => return Some(Err(e).map_err(NE::from)),
             }
         }
 
diff --git a/lib/domain/libimagtimetrack/src/iter/get.rs b/lib/domain/libimagtimetrack/src/iter/get.rs
index e0433958..fdb55c20 100644
--- a/lib/domain/libimagtimetrack/src/iter/get.rs
+++ b/lib/domain/libimagtimetrack/src/iter/get.rs
@@ -37,12 +37,15 @@ impl<'a> Iterator for TimeTrackingsGetIterator<'a> {
 
     fn next(&mut self) -> Option<Self::Item> {
         while let Some(next) = self.0.next() {
-            if next.is_in_collection(&[CRATE_NAME]) {
-                return match self.1.get(next) {
-                    Ok(Some(fle)) => Some(Ok(fle)),
-                    Ok(None)      => continue,
-                    Err(e)        => Some(Err(e))
-                };
+            match next {
+                Err(e)   => return Some(Err(e)),
+                Ok(next) => if next.is_in_collection(&[CRATE_NAME]) {
+                    return match self.1.get(next) {
+                        Ok(Some(fle)) => Some(Ok(fle)),
+                        Ok(None)      => continue,
+                        Err(e)        => Some(Err(e))
+                    };
+                }
             }
         }
 
diff --git a/lib/domain/libimagtimetrack/src/iter/mod.rs b/lib/domain/libimagtimetrack/src/iter/mod.rs
index f0648ce2..556d8b93 100644
--- a/lib/domain/libimagtimetrack/src/iter/mod.rs
+++ b/lib/domain/libimagtimetrack/src/iter/mod.rs
@@ -26,6 +26,8 @@ pub mod tag;
 
 #[cfg(test)]
 mod test {
+    use std::sync::Arc;
+
     use chrono::naive::NaiveDate;
 
     use libimagstore::store::Store;
@@ -37,7 +39,7 @@ mod test {
         use std::path::PathBuf;
         use libimagstore::file_abstraction::InMemoryFileAbstraction;
 
-        let backend = Box::new(InMemoryFileAbstraction::default());
+        let backend = Arc::new(InMemoryFileAbstraction::default());
         Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
     }
 
diff --git a/lib/domain/libimagtodo/src/iter.rs b/lib/domain/libimagtodo/src/iter.rs
index c2871c5a..c5c63943 100644
--- a/lib/domain/libimagtodo/src/iter.rs
+++ b/lib/domain/libimagtodo/src/iter.rs
@@ -20,6 +20,9 @@
 use libimagstore::storeid::StoreIdIterator;
 use libimagstore::storeid::StoreId;
 
+use error::Result;
+use error::TodoError as TE;
+
 pub struct TaskIdIterator(StoreIdIterator);
 
 impl TaskIdIterator {
@@ -31,14 +34,15 @@ impl TaskIdIterator {
 }
 
 impl Iterator for TaskIdIterator {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
     fn next(&mut self) -> Option<Self::Item> {
         loop {
             match self.0.next() {
                 None    => return None,
-                Some(n) => if n.is_in_collection(&["todo", "taskwarrior"]) {
-                    return Some(n)
+                Some(Err(e)) => return Some(Err(e).map_err(TE::from)),
+                Some(Ok(n)) => if n.is_in_collection(&["todo", "taskwarrior"]) {
+                    return Some(Ok(n))
                 }, // else continue
             }
         }
diff --git a/lib/domain/libimagwiki/src/wiki.rs b/lib/domain/libimagwiki/src/wiki.rs
index 50ef61cd..0612bec8 100644
--- a/lib/domain/libimagwiki/src/wiki.rs
+++ b/lib/domain/libimagwiki/src/wiki.rs
@@ -108,12 +108,15 @@ impl<'a, 'b> Wiki<'a, 'b> {
 pub struct WikiIdIterator<'a>(StoreIdIteratorWithStore<'a>, IdIsInWikiFilter<'a>);
 
 impl<'a> Iterator for WikiIdIterator<'a> {
-    type Item = StoreId;
+    type Item = Result<StoreId>;
 
     fn next(&mut self) -> Option<Self::Item> {
         while let Some(next) = self.0.next() {
-            if self.1.filter(&next) {
-                return Some(next)
+            match next {
+                Ok(next) => if self.1.filter(&next) {
+                    return Some(Ok(next));
+                },
+                Err(e) => return Some(Err(e).map_err(WE::from)),
             }
         }
 
diff --git a/lib/entry/libimagentryannotation/src/annotateable.rs b/lib/entry/libimagentryannotation/src/annotateable.rs
index 4906b174..d38b9c66 100644
--- a/lib/entry/libimagentryannotation/src/annotateable.rs
+++ b/lib/entry/libimagentryannotation/src/annotateable.rs
@@ -92,7 +92,7 @@ impl Annotateable for Entry {
     fn annotations<'a>(&self, store: &'a Store) -> Result<AnnotationIter<'a>> {
         self.get_internal_links()
             .map_err(From::from)
-            .map(|iter| StoreIdIterator::new(Box::new(iter.map(|e| e.get_store_id().clone()))))
+            .map(|iter| StoreIdIterator::new(Box::new(iter.map(|e| e.get_store_id().clone()).map(Ok))))
             .map(|i| AnnotationIter::new(i, store))
     }
 
diff --git a/lib/entry/libimagentryannotation/src/iter.rs b/lib/entry/libimagentryannotation/src/iter.rs
index 996c6ffd..9485ba07 100644
--- a/lib/entry/libimagentryannotation/src/iter.rs
+++ b/lib/entry/libimagentryannotation/src/iter.rs
@@ -24,6 +24,7 @@ use libimagstore::store::FileLockEntry;
 use libimagstore::storeid::StoreIdIterator;
 
 use error::Result;
+use error::AnnotationError as AE;
 use error::AnnotationErrorKind as AEK;
 use error::ResultExt;
 
@@ -43,18 +44,21 @@ impl<'a> Iterator for AnnotationIter<'a> {
 
     fn next(&mut self) -> Option<Self::Item> {
         loop {
-            match self.0.next().map(|id| self.1.get(id)) {
-                Some(Ok(Some(entry))) => {
-                    match entry.get_header().read_bool("annotation.is_annotation").chain_err(|| AEK::HeaderReadError) {
-                        Ok(None)        => continue, // not an annotation
-                        Ok(Some(false)) => continue,
-                        Ok(Some(true))  => return Some(Ok(entry)),
-                        Err(e)          => return Some(Err(e)),
-                    }
-                },
-                Some(Ok(None)) => continue,
-                Some(Err(e))   => return Some(Err(e).chain_err(|| AEK::StoreReadError)),
-                None           => return None, // iterator consumed
+            match self.0.next() {
+                None         => return None, // iterator consumed
+                Some(Err(e)) => return Some(Err(e).map_err(AE::from)),
+                Some(Ok(id)) => match self.1.get(id) {
+                    Err(e)          => return Some(Err(e).chain_err(|| AEK::StoreReadError)),
+                    Ok(Some(entry)) => {
+                        match entry.get_header().read_bool("annotation.is_annotation").chain_err(|| AEK::HeaderReadError) {
+                            Ok(None)        => continue, // not an annotation
+                            Ok(Some(false)) => continue,
+                            Ok(Some(true))  => return Some(Ok(entry)),
+                            Err(e)          => return Some(Err(e)),
+                        }
+                    },
+                    Ok(None) => continue,
+                }
             }
         }
     }
diff --git a/lib/entry/libimagentrycategory/src/category.rs b/lib/entry/libimagentrycategory/src/category.rs
index fab8715f..8da3342f 100644
--- a/lib/entry/libimagentrycategory/src/category.rs
+++ b/lib/entry/libimagentrycategory/src/category.rs
@@ -55,7 +55,7 @@ impl Category for Entry {
 
     fn get_entries<'a>(&self, store: &'a Store) -> Result<CategoryEntryIterator<'a>> {
         trace!("Getting linked entries for category '{:?}'", self.get_location());
-        let sit  = self.get_internal_links()?.map(|l| l.get_store_id().clone());
+        let sit  = self.get_internal_links()?.map(|l| l.get_store_id().clone()).map(Ok);
         let sit  = StoreIdIterator::new(Box::new(sit));
         let name = self.get_name()?;
         Ok(CategoryEntryIterator::new(store, sit, name))
diff --git a/lib/entry/libimagentrycategory/src/iter.rs b/lib/entry/libimagentrycategory/src/iter.rs
index a835b82a..ac143025 100644
--- a/lib/entry/libimagentrycategory/src/iter.rs
+++ b/lib/entry/libimagentrycategory/src/iter.rs
@@ -60,18 +60,23 @@ impl<'a> Iterator for CategoryNameIter<'a> {
         let query = CATEGORY_REGISTER_NAME_FIELD_PATH;
 
         while let Some(sid) = self.1.next() {
-            if sid.is_in_collection(&["category"]) {
-                let func = |store: &Store| { // hack for returning Some(Result<_, _>)
-                    store
-                        .get(sid)?
-                        .ok_or_else(|| CE::from_kind(CEK::StoreReadError))?
-                        .get_header()
-                        .read_string(query)
-                        .chain_err(|| CEK::HeaderReadError)?
-                        .ok_or_else(|| CE::from_kind(CEK::StoreReadError))
-                };
+            match sid {
+                Err(e) => return Some(Err(e).map_err(CE::from)),
+                Ok(sid) => {
+                    if sid.is_in_collection(&["category"]) {
+                        let func = |store: &Store| { // hack for returning Some(Result<_, _>)
+                            store
+                                .get(sid)?
+                                .ok_or_else(|| CE::from_kind(CEK::StoreReadError))?
+                                .get_header()
+                                .read_string(query)
+                                .chain_err(|| CEK::HeaderReadError)?
+                                .ok_or_else(|| CE::from_kind(CEK::StoreReadError))
+                        };
 
-                return Some(func(&self.0))
+                    return Some(func(&self.0))
+                    }
+                },
             } // else continue
         }
 
@@ -92,20 +97,25 @@ impl<'a> Iterator for CategoryEntryIterator<'a> {
 
     fn next(&mut self) -> Option<Self::Item> {
         while let Some(next) = self.1.next() {
-            let getter = |next| -> Result<(String, FileLockEntry<'a>)> {
-                let entry = self.0
-                    .get(next)?
-                    .ok_or_else(|| CE::from_kind(CEK::StoreReadError))?;
-                Ok((entry.get_category()?, entry))
-            };
+            match next {
+                Err(e) => return Some(Err(e).map_err(CE::from)),
+                Ok(next) => {
+                    let getter = |next| -> Result<(String, FileLockEntry<'a>)> {
+                        let entry = self.0
+                            .get(next)?
+                            .ok_or_else(|| CE::from_kind(CEK::StoreReadError))?;
+                        Ok((entry.get_category()?, entry))
+                    };
 
-            match getter(next) {
-                Err(e)     => return Some(Err(e)),
-                Ok((c, e)) => {
-                    if c == self.2 {
-                        return Some(Ok(e))
-                    // } else {
-                    // continue
+                    match getter(next) {
+                        Err(e)     => return Some(Err(e)),
+                        Ok((c, e)) => {
+                            if c == self.2 {
+                                return Some(Ok(e))
+                            // } else {
+                            // continue
+                            }
+                        }
                     }
                 }
             }
diff --git a/lib/entry/libimagentrycategory/src/store.rs b/lib/entry/libimagentrycategory/src/store.rs
index e1fb929a..8179010d 100644
--- a/lib/entry/libimagentrycategory/src/store.rs
+++ b/lib/entry/libimagentrycategory/src/store.rs
@@ -111,6 +111,7 @@ impl CategoryStore for Store {
 mod tests {
     extern crate env_logger;
     use std::path::PathBuf;
+    use std::sync::Arc;
 
     use super::*;
 
@@ -118,7 +119,7 @@ mod tests {
 
     pub fn get_store() -> Store {
         use libimagstore::store::InMemoryFileAbstraction;
-        let backend = Box::new(InMemoryFileAbstraction::default());
+        let backend = Arc::new(InMemoryFileAbstraction::default());
         Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
     }
 
diff --git a/lib/entry/libimagentrydatetime/src/datetime.rs b/lib/entry/libimagentrydatetime/src/datetime.rs
index 6eb6683d..790f9f84 100644
--- a/lib/entry/libimagentrydatetime/src/datetime.rs
+++ b/lib/entry/libimagentrydatetime/src/datetime.rs
@@ -195,7 +195,7 @@ fn val_to_ndt(v: &Value) -> Result<NaiveDateTime> {
 #[cfg(test)]
 mod tests {
     use std::path::PathBuf;
-    use toml_query::read::TomlValueReadExt;
+    use std::sync::Arc;
 
     use super::*;
 
@@ -204,10 +204,11 @@ mod tests {
     use chrono::naive::NaiveDateTime;
     use chrono::naive::NaiveDate;
     use chrono::naive::NaiveTime;
+    use toml_query::read::TomlValueReadExt;
 
     pub fn get_store() -> Store {
         use libimagstore::store::InMemoryFileAbstraction;
-        let backend = Box::new(InMemoryFileAbstraction::default());
+        let backend = Arc::new(InMemoryFileAbstraction::default());
         Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
     }
 
diff --git a/lib/entry/libimagentrygps/src/entry.rs b/lib/entry/libimagentrygps/src/entry.rs
index 37acb075..d6eb4be7 100644
--- a/lib/entry/libimagentrygps/src/entry.rs
+++ b/lib/entry/libimagentrygps/src/entry.rs
@@ -102,6 +102,7 @@ impl GPSEntry for Entry {
 #[cfg(test)]
 mod tests {
     use std::path::PathBuf;
+    use std::sync::Arc;
 
     use libimagstore::store::Store;
 
@@ -113,7 +114,7 @@ mod tests {
 
     fn get_store() -> Store {
         use libimagstore::file_abstraction::InMemoryFileAbstraction;
-        let backend = Box::new(InMemoryFileAbstraction::default());
+        let backend = Arc::new(InMemoryFileAbstraction::default());
         Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
     }
 
diff --git a/lib/entry/libimagentrylink/src/external.rs b/lib/entry/libimagentrylink/src/external.rs
index 4d7d48bc..2d5592c6 100644
--- a/lib/entry/libimagentrylink/src/external.rs
+++ b/lib/entry/libimagentrylink/src/external.rs
@@ -406,6 +406,7 @@ impl ExternalLinker for Entry {
 mod tests {
     use super::*;
     use std::path::PathBuf;
+    use std::sync::Arc;
 
     use libimagstore::store::Store;
 
@@ -416,7 +417,7 @@ mod tests {
 
     pub fn get_store() -> Store {
         use libimagstore::file_abstraction::InMemoryFileAbstraction;
-        let backend = Box::new(InMemoryFileAbstraction::default());
+        let backend = Arc::new(InMemoryFileAbstraction::default());
         Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
     }
 
diff --git a/lib/entry/libimagentrylink/src/internal.rs b/lib/entry/libimagentrylink/src/internal.rs
index e7c06fd7..480a07bc 100644
--- a/lib/entry/libimagentrylink/src/internal.rs
+++ b/lib/entry/libimagentrylink/src/internal.rs
@@ -772,6 +772,7 @@ pub mod store_check {
 #[cfg(test)]
 mod test {
     use std::path::PathBuf;
+    use std::sync::Arc;
 
     use libimagstore::store::Store;
 
@@ -784,7 +785,7 @@ mod test {
 
     pub fn get_store() -> Store {
         use libimagstore::file_abstraction::InMemoryFileAbstraction;
-        let backend = Box::new(InMemoryFileAbstraction::default());
+        let backend = Arc::new(InMemoryFileAbstraction::default());
         Store::new_with_backend(PathBuf::from("/"), &None, backend).unwrap()
     }
 
diff --git a/lib/entry/libimagentrymarkdown/src/processor.rs b/lib/entry/libimagentrymarkdown/src/processor.rs
index f9b085a5..5fddcd9e 100644
--- a/lib/entry/libimagentrymarkdown/src/processor.rs
+++ b/lib/entry/libimagentrymarkdown/src/processor.rs
@@ -233,6 +233,7 @@ mod tests {
     use super::*;
 
     use std::path::PathBuf;
+    use std::sync::Arc;
 
     use libimagstore::store::Store;
     use libimagentrylink::internal::InternalLinker;
@@ -244,7 +245,7 @@ mod tests {
     pub fn get_store() -> Store {
         use libimagstore::file_abstraction::InMemoryFileAbstraction;
         let fs = InMemoryFileAbstraction::default();
-        Store::new_with_backend(PathBuf::from("/"), &None, Box::new(fs)).unwrap()
+        Store::new_with_backend(PathBuf::from("/"), &None, Arc::new(fs)).unwrap()
     }
 
     #[test]