--- Remotely Modified (Based On HEAD)
+++ Locally Modified (Based On LOCAL)
@@ -158,6 +158,12 @@
  * Takes care of scheduled backups and deletes abandoned temp files.
  */
 function backup_migrate_cron() {
+
+  // test if we're already (called by another request)
+  if(!lock_acquire('backup_migrate_running', 60)) {
+    return;
+  }
+
   // Set the message mode to logging.
   _backup_migrate_message_callback('_backup_migrate_message_log');
 
@@ -166,6 +172,9 @@
 
   backup_migrate_include('files');
   _backup_migrate_temp_files_delete();
+
+  // release lock
+  lock_release('backup_migrate_running');
 }
 
 /**