Oct 31, 2013 12:51 AM|Happy Chen - MSFT|LINK
hi cabbry ,
May 2012 release of
AjaxControlToolkit includes a new AjaxFileUpload Control which supports
Multiple File Upload, Progress Bar and Drag And Drop functionality.
These new features are supported by Google Chrome version 16+, Firefox 8+ , Safari 5+ and Internet explorer 10 + , IE9 or earlier does not support this feature.
I sugeest you try to set ThrobberID property .
ThrobberID is used to display loading image instead of progress bar in unsupported browsers.
Please read the reference below for more information:
Asp.Net AjaxFileUpload Control With Drag Drop And Progress Bar
Hope it helps you.