diff --git a/src/calibre/gui2/tag_browser/model.py b/src/calibre/gui2/tag_browser/model.py
index 2d6f40690b..742f2b2776 100644
--- a/src/calibre/gui2/tag_browser/model.py
+++ b/src/calibre/gui2/tag_browser/model.py
@@ -188,12 +188,14 @@ class TagTreeItem(object): # {{{
 
     def child_tags(self):
         res = []
-        def recurse(nodes, res):
+        def recurse(nodes, res, depth):
+            if depth > 100:
+                return
             for t in nodes:
                 if t.type != TagTreeItem.CATEGORY:
                     res.append(t)
-                recurse(t.children, res)
-        recurse(self.children, res)
+                recurse(t.children, res, depth+1)
+        recurse(self.children, res, 1)
         return res
     # }}}