diff --git a/backup/restore_execute.html b/backup/restore_execute.html
index 960c5293319..872b422e65d 100644
--- a/backup/restore_execute.html
+++ b/backup/restore_execute.html
@@ -64,6 +64,7 @@
     //Saving conversion id variables into backup_tables
     if ($restore->restoreto == 2) {
         echo "<li>".get_string("creatingnewcourse");
+        $oldidnumber = $course_header->course_idnumber;
         if (!$status = restore_create_new_course($restore,$course_header)) {
             notify("Error while creating the new empty course.");
         }
@@ -72,6 +73,9 @@
             echo "<ul>";
             echo "<li>".$course_header->course_fullname." (".$course_header->course_shortname.")";
             echo "<li>".get_string("category").": ".$course_header->category->name;
+            if (!empty($oldidnumber)) {
+                echo "<li>".get_string("nomoreidnumber","moodle",$oldidnumber)."</li>";
+            }
             echo "</ul>";
             //Put the destination course_id
             $restore->course_id = $course_header->course_id;
diff --git a/backup/restorelib.php b/backup/restorelib.php
index 1dd612a0c44..1a18fbaa554 100644
--- a/backup/restorelib.php
+++ b/backup/restorelib.php
@@ -518,6 +518,7 @@
             $course->fullname = addslashes($course_header->course_fullname);
             $course->shortname = addslashes($course_header->course_shortname);
             $course->idnumber = addslashes($course_header->course_idnumber);
+            $course->idnumber = ''; //addslashes($course_header->course_idnumber); // we don't want this at all.
             $course->summary = restore_decode_absolute_links(addslashes($course_header->course_summary));
             $course->format = addslashes($course_header->course_format);
             $course->showgrades = addslashes($course_header->course_showgrades);
diff --git a/lang/en/moodle.php b/lang/en/moodle.php
index 0332e335f70..82c070a5d63 100644
--- a/lang/en/moodle.php
+++ b/lang/en/moodle.php
@@ -767,6 +767,7 @@ $string['nofilesyet'] = 'No files have been uploaded to your course yet';
 $string['nograde'] = 'No grade';
 $string['noimagesyet'] = 'No images have been uploaded to your course yet';
 $string['nomorecourses'] = 'No more matching courses could be found';
+$string['nomoreidnumber'] = 'Not using an idnumber to avoid collisions';
 $string['none'] = 'None';
 $string['nopotentialadmins'] = 'No potential admins';
 $string['nopotentialcreators'] = 'No potential course creators';