It seems that Drag and Drop function of the AjaxFileUpload control is not working on IE10 (tested in IE10 for Windows 7).
For example the official sample (just try it yourself : http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/AjaxFileUpload/AjaxFileUpload.aspx) is working well in Chrome and Firefox, but not in IE10.
Comments: The issue is fixed and the fix is included in the future release. Related changeset: [be60be2](https://ajaxcontroltoolkit.codeplex.com/SourceControl/changeset/be60be2cf8e36629ef5f2367ce29f52d50a548c8) Please try a workaround if you have corrupted form data in IE 10: https://blog.yorkxin.org/posts/2014/02/06/ajax-with-formdata-is-broken-on-ie10-ie11/
For example the official sample (just try it yourself : http://www.asp.net/ajaxLibrary/AjaxControlToolkitSampleSite/AjaxFileUpload/AjaxFileUpload.aspx) is working well in Chrome and Firefox, but not in IE10.
Comments: The issue is fixed and the fix is included in the future release. Related changeset: [be60be2](https://ajaxcontroltoolkit.codeplex.com/SourceControl/changeset/be60be2cf8e36629ef5f2367ce29f52d50a548c8) Please try a workaround if you have corrupted form data in IE 10: https://blog.yorkxin.org/posts/2014/02/06/ajax-with-formdata-is-broken-on-ie10-ie11/