diff --git a/src/calibre/library/server/browse.py b/src/calibre/library/server/browse.py
index 5c2ffe7865..a770f19856 100644
--- a/src/calibre/library/server/browse.py
+++ b/src/calibre/library/server/browse.py
@@ -358,7 +358,10 @@ class BrowseServer(object):
             cats.append((_('Virtual Libs.'), 'virt_libs', 'lt.png'))
 
         def getter(x):
-            return category_meta[x]['name'].lower()
+            try:
+                return category_meta[x]['name'].lower()
+            except KeyError:
+                return x
 
         displayed_custom_fields = custom_fields_to_display(self.db)
         uc_displayed = set()