diff --git a/src/pyj/book_list/custom_list.pyj b/src/pyj/book_list/custom_list.pyj
index 080236dba7..3cafe9d7da 100644
--- a/src/pyj/book_list/custom_list.pyj
+++ b/src/pyj/book_list/custom_list.pyj
@@ -61,6 +61,8 @@ def render_field(field, mi, book_id):  # {{{
     if field is 'id':
         return book_id + ''
     field_metadata = library_data.field_metadata
+    if not field_metadata:
+        return
     fm = field_metadata[field]
     if not fm or not mi:
         return