--- a/server/src/assets/js/mtdc-tracking-worker.js	Mon Jul 25 16:18:59 2016 +0200
+++ b/server/src/assets/js/mtdc-tracking-worker.js	Mon Jul 25 16:29:56 2016 +0200
@@ -187,7 +187,7 @@
                 $.ajax({
                     method: 'POST',
                     url: this.trackingCloseUrl,
-                    async: true,
+                    async: false,
                     headers: {
                         'X-CSRFToken': this.csrftoken
                     },