Same symptom on 2 separate servers:
After the upgrade I try to login and get "Authentication failed. Please try again."
We've tried this with 3 separate admin level accounts. We are normally configured to use ACS.
I did the typical installation with optional packages unchecked.
I tried restarting crmdmgtd and have tried running ResetLoginModule.pl (and restarting daemon manager). No luck so far. Any suggestions?