diff --git a/src/calibre/library/server/browse.py b/src/calibre/library/server/browse.py
index 37f024c08d..485601a311 100644
--- a/src/calibre/library/server/browse.py
+++ b/src/calibre/library/server/browse.py
@@ -373,13 +373,18 @@ class BrowseServer(object):
                     script='toplevel();', main=main)
 
     def browse_sort_categories(self, items, sort):
-        if sort not in ('rating', 'name', 'popularity'):
-            sort = 'name'
-        items.sort(key=lambda x: sort_key(getattr(x, 'sort', x.name)))
+        def keyg(x):
+            x = getattr(x, 'sort', x.name)
+            if isinstance(x, unicode):
+                return sort_key(x)
+            return x
+
         if sort == 'popularity':
             items.sort(key=operator.attrgetter('count'), reverse=True)
         elif sort == 'rating':
             items.sort(key=operator.attrgetter('avg_rating'), reverse=True)
+        else:
+            items.sort(key=keyg)
         return sort
 
     def browse_category(self, category, sort):