diff --git a/src/calibre/library/server/browse.py b/src/calibre/library/server/browse.py
index 7dfedcb6ff..0e132c7d11 100644
--- a/src/calibre/library/server/browse.py
+++ b/src/calibre/library/server/browse.py
@@ -673,6 +673,8 @@ class BrowseServer(object):
                         categories = [categories]
                     dbtags = []
                     for category in categories:
+                        if category not in ccache:
+                            continue
                         dbtag = None
                         for tag in ccache[key]:
                             if tag.name == category: