In my very large SP2010 production site. I used classic mode of authentication (no claims) and in my inetmgr for all sp2010 web applications, I had anonymous, basic, digest and forms authentication disabled.
only windows authentication and asp.net impersonation were enabled and life was good.
Now I have tested this in two different environments.
A SP2013 claims based windows identity web application stops working if I try to disable "forms authentication"
This doesn't make any sense to me.
I have done this many times. everything works... just disable "forms authentication" in inetmgr for sharepoint web app,do iisreset, and try to access any site and it will say "this site has not been shared with you" even though my account is farm admin and site collection admin and local admin on all boxes of the farm including SQL.
and if I enable "forms authentication" (and do iisreset) then it works as expected.
But this is strange and crazy behavior .... why.... why can't forms authentication be disabled in a claims based, windows identity web applications??
