A new KB article was released today related to a specific situation that leads to a user profile folder being created with the UPN as the name of the folder instead of the sAMAccountname.
“…Consider the following scenario:
- You have a client computer that is running Windows 7 or Windows Server 2008 R2 in an Active Directory domain.
- You enable the User must change password at next logon option for the domain users.
- You log on to a client computer by using a user principal name (UPN).
- The user profile folder is created on the client computer.
User name@domain name
- The expected format of user profile folder name is in the sAMAccountName format.
- This issue only occurs when you log on to a client computer for the first time. When you log on to the client computer again, the user profile folder is in the sAMAccountName format as expected…”
Source and fix: http://support.microsoft.com/kb/2748437/en-us?sd=rss&spid=14134