diff --git a/src/calibre/gui2/tag_browser/view.py b/src/calibre/gui2/tag_browser/view.py
index d53167591e..295ef6f452 100644
--- a/src/calibre/gui2/tag_browser/view.py
+++ b/src/calibre/gui2/tag_browser/view.py
@@ -575,7 +575,9 @@ class TagsView(QTreeView): # {{{
         expanded_categories, state_map = self.get_state()
         self._model.rebuild_node_tree(state_map=state_map)
         for category in expanded_categories:
-            self.expand(self._model.index_for_category(category))
+            idx = self._model.index_for_category(category)
+            if idx is not None and idx.isValid():
+                self.expand(idx)
         self.show_item_at_path(path)
 
     def show_item_at_path(self, path, box=False,