Run logon scripts synchronously
Computer Configuration\Administrative Templates\System\Logon
Directs the system to wait for logon scripts to finish running before it starts the Windows Explorer interface program and creates the desktop.
If you enable this policy, Windows Explorer does not start until the logon scripts have finished running. This setting assures that logon script processing is complete before the user starts working, but it can delay the appearance of the desktop.
If you disable this policy or do not configure it, the logon scripts and Windows Explorer are not synchronized and can run simultaneously.
This policy appears in the Computer Configuration and User Configuration folders. The policy set in Computer Configuration takes precedence over the policy set in User Configuration.