At the High School we have one lab of PC’s that run Vista.  After updating the default profile to include some new printers and drivers I was made aware that most users where being logged in with a Temp profile which is deleted on logout.  It turns out that if you delete the users from the c:\USERS directory in Vista, registry entries still exist for all of the unique logins for that machine.  If a user returns to this machine Vista will get confused as there is not a directory on the hard drive for this user but instead there exists a user entry in the registry refering to one.  This problem does not seem to affect administrator accounts or accounts that are part of the local admin’s group.

The easiest fix I could find is to login to each machine as Admin,  then delete the Profile list registry entries which are located at Local Machine | Software | Microsoft | Windows NT | Current | ProfileList

Here I just deleted all of the entries except for the top three which refer to the system accounts. This problem only seems to appear on Vista based machines,  deleting Users profiles on XP does not seem to cause this glitch.