diff --git a/mod/wiki/renderer.php b/mod/wiki/renderer.php
index 31594b2..c103957 100755
--- a/mod/wiki/renderer.php
+++ b/mod/wiki/renderer.php
@@ -389,6 +389,9 @@ class mod_wiki_renderer extends plugin_renderer_base {
                         }
                     }
                 } else {
+                    if ($subwiki->groupid == 0){
+                        return ;
+                    }
                     $group = groups_get_group($subwiki->groupid);
                     $users = groups_get_members($subwiki->groupid);
                     foreach ($users as $user) {