diff --git a/borg/archiver.py b/borg/archiver.py
index 77f1a6267..8f7120037 100644
--- a/borg/archiver.py
+++ b/borg/archiver.py
@@ -471,7 +471,7 @@ def compare_link(item1, item2):
                 return 'added link'
             elif item2.get(b'deleted'):
                 return 'removed link'
-            elif item1[b'source'] != item2[b'source']:
+            elif b'source' in item1 and b'source' in item2 and item1[b'source'] != item2[b'source']:
                 return 'changed link'
 
         def contents_changed(item1, item2):