diff --git a/libimagstore/src/store.rs b/libimagstore/src/store.rs
index e0f80876..d195e067 100644
--- a/libimagstore/src/store.rs
+++ b/libimagstore/src/store.rs
@@ -95,6 +95,8 @@ impl StoreEntry {
             let file = try!(self.file.create_file());
 
             assert_eq!(self.id, entry.location);
+            try!(file.set_len(0)
+                .map_err(|e| StoreError::new(StoreErrorKind::FileError, Some(Box::new(e)))));
             file.write_all(entry.to_str().as_bytes())
                 .map_err(|e| StoreError::new(StoreErrorKind::FileError, Some(Box::new(e))))
         } else {