diff --git a/app/controllers/course/studygroup.php b/app/controllers/course/studygroup.php
index c1e7b4831c82b012349712ee8375804063bed931..db54b97d84c92d950469fbe97a2cdab2fae79b39 100644
--- a/app/controllers/course/studygroup.php
+++ b/app/controllers/course/studygroup.php
@@ -367,7 +367,7 @@ class Course_StudygroupController extends AuthenticatedController
         PageLayout::setHelpKeyword('Basis.StudiengruppenBearbeiten');
 
         // if we are permitted to edit the studygroup get some data...
-        if ($perm->have_studip_perm('dozent', $id)) {
+        if ($id && $perm->have_studip_perm('dozent', $id)) {
             $sem = Seminar::getInstance($id);
 
             PageLayout::setTitle(Context::getHeaderLine() . ' - ' . _('Studiengruppe bearbeiten'));