I have a machine on the network that was having problems, looked like a profile problem so I backed up, rebooted, logged in as administrator, renamed c:\users\username to xusername and rebooted again and logged in. It told me it had logged me in as a temporary profile. I logged out and back in again same thing again. The issue has gone, but it won't keep the settings.
I tried recreating the same folder name and giving it the same rights, no luck.
Also I see an event log entry about being unable to access the profile path.
Windows 7 SP1, x64. Connecting to a 2003 Domain.