---
title: IE10 and IE11 browsers freeze when RadAsyncUpload is used in SharePoint application with NTLM authentication turned on
page_title: IE10 and IE11 freeze when RadAsyncUpload is used in SharePoint application with NTLM authentication turned on | RadAsyncUpload for ASP.NET AJAX Documentation
description: IE10 and IE11 freeze when RadAsyncUpload is used in SharePoint application with NTLM authentication turned on
slug: asyncupload\troubleshooting\radasyncupload-freezes-in-ie10-ie11-when-ntlm-authentication-is-used-in-sharepoint
tags: asyncupload,ie,ie10,ie11,sharepoint,ntml,authentication
published: True
position: 0
---

# IE10 and IE11 browsers freeze when RadAsyncUpload is used in SharePoint application with NTLM authentication turned on



## 

The **FileApi** implementation in **Internet explorer 10 and 11** conflicts with the NTLM authentication in **SharePoint**. As the RadAsyncUpload control uses the **FileApi module**, using it in a **SharePoint** project with the above authentication enabled, results in browser freeze. The file uploading request receives response with code 401 (Unauthorized), blocking in this way the functionality of the control and the whole page.

The above has been reported to be an [Internet explorer bug](https://connect.microsoft.com/IE/feedback/details/819941/file-upload-stop-working-on-ie-with-windows-authentication).

In order to resolve this issue, the FileApi module for the RadAsyncUpload should be disabled:

````ASPNET
<script type="text/javascript">
    Telerik.Web.UI.RadAsyncUpload.Modules.FileApi.isAvailable = function () {
		return false;
	}
  </script>
````


Add troubleshoting documentation article - RadAsyncUpload in IE10, IE11 with NTLM authentication in Sharepoint
Add troubleshoting documentation article - RadAsyncUpload in IE10, IE11 with NTLM authentication in Sharepoint
