Valums file-uploader (now called Fine Uploader) doesn’t work under Internet Explorer 9 but wors fine under Chrome.
So under IE it shows the name of the file and button CANCEL and no % of uploading.
Any clue?

UPDATES:
Solution is here as well MVC Valums Ajax Uploader – IE doesn't send the stream in request.InputStream
I know this question was filed under asp.net specifically, but it came up when I searched for “valums ajax upload IE9”, so I’ll post my fix here in case it helps anyone like myself regardless of language:
I was returning a JSON response from the AJAX upload request with a “application/json” content header. IE9 does not know what to do with “application/json” content (but Chrome/FF/etc do).
I fixed this by making sure to return a “text/html” MIME type http header on my json response from the server.
Now IE is no longer trying to download the response! Cheers