You experience a long domain logon time in Windows 7 or in Windows Server 2008 R2 after you deploy Group Policy preferences to the computer

“You experience a long domain logon time in Windows 7 or in Windows Server 2008 R2 after you deploy Group Policy preferences to the computer“, http://support.microsoft.com/?kbid=2561285

There’s a hotfix for Win7 and Server 2008 R2 available.