diff --git a/beets/ui/__init__.py b/beets/ui/__init__.py
index 8daefa12a..ac919d7d2 100644
--- a/beets/ui/__init__.py
+++ b/beets/ui/__init__.py
@@ -59,8 +59,8 @@ log.propagate = False  # Don't propagate to root handler.
 
 
 PF_KEY_QUERIES = {
-    'comp': 'comp:true',
-    'singleton': 'singleton:true',
+    'comp': u'comp:true',
+    'singleton': u'singleton:true',
 }
 
 
diff --git a/beetsplug/mbsync.py b/beetsplug/mbsync.py
index 56513353a..cf58c82d5 100644
--- a/beetsplug/mbsync.py
+++ b/beetsplug/mbsync.py
@@ -75,7 +75,7 @@ class MBSyncPlugin(BeetsPlugin):
         """Retrieve and apply info from the autotagger for items matched by
         query.
         """
-        for item in lib.items(query + ['singleton:true']):
+        for item in lib.items(query + [u'singleton:true']):
             item_formatted = format(item)
             if not item.mb_trackid:
                 self._log.info(u'Skipping singleton with no mb_trackid: {0}',