I am running XP SP3 and logging into a Windows Vista machine using RDP 6.1 (also tried 7.0) with NLA. I've done the registry configuration enabling SSO (although reproduced this without those registry entries using fresh credentials). The first logon works perfectly. I log off the Vista machine. Then, the second login comes up with "An authentication error occurred (0xc00002fd)." I can never get another login to work. I reboot XP and it will work again, once. The error appears to be some kind of encryption issue. Could it be that CredSSP is caching something that does not work? Any help greatly appreciated!1 person needs an answerI do too