diff --git a/backup/moodle2/restore_stepslib.php b/backup/moodle2/restore_stepslib.php
index 111dfac90c5..c9038cfc954 100644
--- a/backup/moodle2/restore_stepslib.php
+++ b/backup/moodle2/restore_stepslib.php
@@ -3051,11 +3051,6 @@ class restore_activity_grades_structure_step extends restore_structure_step {
         $oldparentid = $data->categoryid;
         $courseid = $this->get_courseid();
 
-        // make sure top course category exists, all grade items will be associated
-        // to it. Later, if restoring the whole gradebook, categories will be introduced
-        $coursecat = grade_category::fetch_course_category($courseid);
-        $coursecatid = $coursecat->id; // Get the categoryid to be used
-
         $idnumber = null;
         if (!empty($data->idnumber)) {
             // Don't get any idnumber from course module. Keep them as they are in grade_item->idnumber
@@ -3080,8 +3075,18 @@ class restore_activity_grades_structure_step extends restore_structure_step {
             }
         }
 
+        if (!empty($data->categoryid)) {
+            // If the grade category id of the grade item being restored belongs to this course
+            // then it is a fair assumption that this is the correct grade category for the activity
+            // and we should leave it in place, if not then unset it.
+            // TODO MDL-34790 Gradebook does not import if target course has gradebook categories.
+            $conditions = array('id' => $data->categoryid, 'courseid' => $courseid);
+            if (!$this->task->is_samesite() || !$DB->record_exists('grade_categories', $conditions)) {
+                unset($data->categoryid);
+            }
+        }
+
         unset($data->id);
-        $data->categoryid   = $coursecatid;
         $data->courseid     = $this->get_courseid();
         $data->iteminstance = $this->task->get_activityid();
         $data->idnumber     = $idnumber;