diff --git a/classes/output/core/course_renderer.php b/classes/output/core/course_renderer.php
index 463f821..53205ea 100755
--- a/classes/output/core/course_renderer.php
+++ b/classes/output/core/course_renderer.php
@@ -46,7 +46,7 @@
  * @copyright  2016 Frédéric Massart - FMCorz.net
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-if ($PAGE->theme->settings->coursetilestyle < 10) {
+if (isset($PAGE->theme->settings->coursetilestyle) && $PAGE->theme->settings->coursetilestyle < 10) {
     class course_renderer extends \core_course_renderer  {
         protected $countcategories = 0;