We have a network domain, all XP pro compters, though the domain controller is NT. I have successfully joined this vista pc, and can 'see' all of the computers and servers on the domain, BUT cannot access any of the shared folders. Can't map to them which is what we usually do, can't browse to them, it asks for a username and password but will not authenticate using good credentials, actually will not even authenticate using the server credentials. I have exhaustively checked the network settings but do not know where else to look. I am using our standard network dns, wins, gateway and IP in TCP/ IPV4 We will soon be moving our 300 pc's to Vista, and this is our test pc, so I need to get this one right before we proceed. I was wondering if it has to do with active directory? We are planning to move to active directory soon as well.