diff --git a/libimaglink/src/error.rs b/libimaglink/src/error.rs
index a57bbbd9..9dfa7533 100644
--- a/libimaglink/src/error.rs
+++ b/libimaglink/src/error.rs
@@ -11,6 +11,7 @@ pub enum LinkErrorKind {
     ExistingLinkTypeWrong,
     LinkTargetDoesNotExist,
     InternalConversionError,
+    InvalidUri,
 }
 
 fn link_error_type_as_str(e: &LinkErrorKind) -> &'static str {
@@ -29,6 +30,9 @@ fn link_error_type_as_str(e: &LinkErrorKind) -> &'static str {
 
         &LinkErrorKind::InternalConversionError
             => "Error while converting values internally",
+
+        &LinkErrorKind::InvalidUri
+            => "URI is not valid",
     }
 }
 
diff --git a/libimaglink/src/external.rs b/libimaglink/src/external.rs
index 59d6c0e1..4b5ff81c 100644
--- a/libimaglink/src/external.rs
+++ b/libimaglink/src/external.rs
@@ -100,6 +100,10 @@ impl ExternalLinker for EntryHeader {
     ///
     /// Return the previous set link if there was any
     fn set_external_link(&mut self, l: Link) -> Result<Option<Link>> {
+        if !l.is_valid() {
+            return Err(LinkError::new(LinkErrorKind::InvalidUri, None));
+        }
+
         let old_link = self.set("imag.content.uri", Value::String(l.into()));
 
         if old_link.is_err() {