Q:

IIS7 IUSR account permissions not working with forms authentication and file upload

I am trying to deploy an asp.net 4 app to a new microsoft server 2008 R2
I have set up the application as I have done dozens of times before and set the folder permissions appropriately.
I have tried setting the application pool name directly to have write permissions
I have tried setting IUSR, IIS_IUSRS, NETWORK SERVICE and Users.
I have confirmed that windows authentication is disabled and anonymous is enabled as well as forms authentication is enabled. Logging in works fine i can access all pages normally except if i try to write to the folder. Then a password is required box pops up which looks like windows authentication (even though its disabled)
Every post here states and in my past experience says if I set the folder permissions for the defaultidentity application pool it should work, but for some reason this server wont let me do it! 
Any help would be most appreciated.

A:

Welp this turns out to be a really weird one. For some reason when SQL reporting services is installed it reserves the folder name "Reports" in any IIS Web application folder regardless of whether your actually using  Reporting services. Its not created by default or anything, but if you happen to create folder titled "Reports" dont expect to access anything from it. After many hours of frustration it turns out it's a random reservation which doesn't throw any error just somehow overrides your authentication protocol to use windows authentication for their reserved folder.
Thanks Microsoft!

