diff --git a/course/renderer.php b/course/renderer.php
index 3e9898cd0c5..1e1d7ad7126 100644
--- a/course/renderer.php
+++ b/course/renderer.php
@@ -92,8 +92,8 @@ class core_course_renderer extends plugin_renderer_base {
      */
     protected function course_category_tree_category(stdClass $category, $depth=1) {
         $content = '';
-        $hassubcategories = (count($category->categories)>0);
-        $hascourses = (count($category->courses)>0);
+        $hassubcategories = (isset($category->categories) && count($category->categories)>0);
+        $hascourses = (isset($category->courses) && count($category->courses)>0);
         $classes = array('category');
         if ($category->parent != 0) {
             $classes[] = 'subcategory';