Referring to the following: Ajax Asyncfileupload doesn't work as soon as I put it in a control
I am having the same issue. I am not using a Master page though. I have an AsyncFileUpload control in a Panel, within an update panel.
Any ideas as to what could be causing the issue?
When you use AsyncFileUpload you must set the right params in the form tag, that is placed in your Page or MasterPage:
<form id="form1" runat="server" enctype="multipart/form-data" method="post">
If you don't set the right enctype and method UploadedComplete will never fire, and you won't be able to get FileUpload.FileBytes since FileUpload.HasFile returns true only during UploadedComplete execution.
I suppose that in your page you haven't set the right enctype.
Besides, prevoius versions of AsyncFileUpload didn't work on Chrome. 2011 July version (4.1.50731.0) solved the problem.