diff --git a/upload/static/js/webuploader.js b/upload/static/js/webuploader.js
index 29567ba16975ce2314cf976916daef507a3cf9f5..a4146cdd4a2548c4cda6b95c94d1479aa89a80cb 100644
--- a/upload/static/js/webuploader.js
+++ b/upload/static/js/webuploader.js
@@ -259,6 +259,7 @@ SWFUpload.prototype.initSettings = function (userSettings) {
 		server: this.settings.upload_url,
 		pick: '#' + this.settings.button_placeholder_id,
 		compress: false,
+		threads: 1,
 		accept: {
 			title: this.settings.file_types_description,
 			extensions: exts,