We are noticing a strange issue with a couple users who are using the Kendo upload.  I don't really understand it and can't reproduce it outside of it being an issue on their PC when running as them.  When they try to upload a file, they don't get any errors, but no file is uploaded.  A 500 error gets reported in IIS logs, but nothing shows up in the event viewer.  They don't even hit our event handler code that they are posting to.  The IE developer tools show "(pending...)" for most of the columns when I look at the post in the network section.  Uploading works fine for almost everyone else though, works as them from computers at other locations, and (the really crazy part) it works as another user at their location.  The only browser they have is IE, and I don't have install rights to put anything else on their PCs.  I'm not sure how much help I can get, since I can't really reproduce this issue, other than some very specific conditions.  I thought I would post it here though, in case anyone had any ideas...

Update: One of the users has IE 10 without compatibility on.  The other user with the issue has IE 9  with IE 7 compatibility on, and it had worked for her until some recent Microsoft update (not this month's patch Tuesday, before that).  The upload control renders fine for both of them. 

Hi,

It's really a shot in the dark, but you may try the following:

• Add your application to the trusted sites list
• Use standards mode (set DOCTYPE and IE meta tag)
• Try an upload from a form with a regular file input
• Try configuring request tracing (IIS 7)
• (On a test server) install Wireshark to get a "raw" network trace

Greetings,
Tsvetomir Tsonev
the Telerik team