On a computer that is running Windows Vista or Windows Server 2008, you enabled the "Run logon scripts synchronously" Group Policy. When you tried to log on, the Welcome screen was displayed for 30 seconds. Then, the logon script interacted with you before the logon script process was completed. For example, the script prompted you to confirm a dialog box.
This issue occurs because the logon process runs in session 0. However, the logon script process runs in a different session. A 30-second delay occurs before Windows Vista switches from session 0 to another session. When the logon script interacts with you before the logon script process is complete, you have to wait for the 30-second time-out interval of session 0. To fix this problem, change the time-out interval to less than 30 seconds.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
To resolve this issue, configure the value of the DelayedDesktopSwitchTimeout registry entry. This value determines the time-out interval of a session before Windows Vista switches between sessions.
To configure the value of the DelayedDesktopSwitchTimeout registry entry, follow these steps:
Click Start, type regedit in the Start Search box, and then press ENTER.