diff --git a/course/lib.php b/course/lib.php
index d0ad4f0660..a475fbd30b 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -3452,6 +3452,14 @@ function duplicate_module($course, $cm) {

     $bc->destroy();

+    // Hack the backup, we want a different name here.
+    $filetohack = $backupbasepath . '/activities/' . $cm->modname . '_' . $cm->id . '/' . $cm->modname . '.xml';
+    // Activity xml files are small enough to be read as a whole.
+    $filecontents = file_get_contents($filetohack);
+    // Of course we must support here lang strings and copy 2, 3, 4...
+    $filecontents = preg_replace('#(<name>)(.*)(</name>)#', '${1}I hacked ${2}!!${3}', $filecontents);
+    file_put_contents($filetohack, $filecontents);
+
     // Restore the backup immediately.

     $rc = new restore_controller($backupid, $course->id,