diff --git a/question/type/edit_question_form.php b/question/type/edit_question_form.php
index 9690d3d9a9e..22e37f0d455 100644
--- a/question/type/edit_question_form.php
+++ b/question/type/edit_question_form.php
@@ -673,7 +673,7 @@ abstract class question_edit_form extends question_wizard_form {
         }
 
         // Default mark.
-        if ($fromform['defaultmark'] < 0) {
+        if (array_key_exists('defaultmark', $fromform) && $fromform['defaultmark'] < 0) {
             $errors['defaultmark'] = get_string('defaultmarkmustbepositive', 'question');
         }