diff --git a/NEWS b/NEWS
index e3ccff98e..066168edb 100644
--- a/NEWS
+++ b/NEWS
@@ -33,6 +33,8 @@
   record would stay around although the items were deleted.
 * The setup script now makes a beet.exe startup stub on Windows; 
   Windows users can now just type "beet" at the prompt to run beets.
+* Fixed an occasional bug where Mutagen would complain that a tag was
+  already present.
 
 1.0b3
 -----
diff --git a/beets/mediafile.py b/beets/mediafile.py
index 7581c57f4..f2ba9f131 100644
--- a/beets/mediafile.py
+++ b/beets/mediafile.py
@@ -492,7 +492,7 @@ class MediaFile(object):
                                 type(self.mgfile).__name__)
         
         # add a set of tags if it's missing
-        if not self.mgfile.tags:
+        if self.mgfile.tags is None:
             self.mgfile.add_tags()
     
     def save(self):