diff --git a/course/lib.php b/course/lib.php
index f295fbd367f..9d08afd4954 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -1359,6 +1359,7 @@ function print_course_search($value="", $return=false, $format="plain") {
 function add_course_module($mod) {
 
     $mod->added = time();
+    unset($mod->id);
 
     return insert_record("course_modules", $mod);
 }