diff --git a/picard/tagger.py b/picard/tagger.py
index 8ac84347a..7e3dd551a 100644
--- a/picard/tagger.py
+++ b/picard/tagger.py
@@ -249,7 +249,7 @@ class Tagger(QtGui.QApplication):
         if album.loaded:
             album.match_files(files)
         else:
-            for file in files:
+            for file in list(files):
                 file.move(album.unmatched_files)
 
     def move_file_to_album(self, file, albumid=None):