When AjaxFileUpload post back it takes your page URL and appends onto the end of it it's own query strings (contextkey and guid). This works fine if your page URL doesn't already contain any query strings but if it does then you end up with a URL that contains two question marks which then corrupts your own final query string value and this in turn stops the upload from working.
Comments: Hello, This issue looks like a blocker to me because not supporting url with querystring avoid us any of us to use the control :-D btw, there is a least 3 similar issues reported, #24917, #27163 , #27155
Comments: Hello, This issue looks like a blocker to me because not supporting url with querystring avoid us any of us to use the control :-D btw, there is a least 3 similar issues reported, #24917, #27163 , #27155