December 9, 2015 –

File uploads are failing due to a MS update that affect IIS.

This is a global issue with multi-part form submissions so users of many applications are having problems so I suspect another patch will fix this problem.

Here is the a thread on the Microsoft IIS site about it:

https://forums.iis.net/p/1229356/2114000.aspx?Re+Windows+Update+breaks+multipart+form+data

That patch is

KB3104002

If you can un-install that patch you can resolve the problem.

We will keep you posted.