The unattended DisableAutoDaylightTimeSet setting has no effect when you set the setting to true on a Windows Vista-based computer. This behavior occurs when the time zone that is used by the computer has dynamic daylight saving time (DST) endpoints. For example, this setting has no effect in the United States.

In Windows Vista, a time zone can have unique DST boundary information every year. For time zones that have dynamic DST endpoints, you must set an additional registry entry to disable automatic switching to DST.

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:
To resolve this issue, follow these steps:

1. Open Windows System Image Manager (Windows SIM).
2. Open a Windows image (.wim) file or a catalog (.clg) file.
3. Open the answer file.
4. In the Windows Image pane, expand Components, and then expand Microsoft-Windows-Deployment.
5. Right-click the RunSynchronous setting, and then add it to the "specialize pass" part of Setup.
6. In the Properties pane, set the following values for this setting:
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   • Path: reg add "HKLM\System\CurrentControlSet\Control\TimeZoneInformation" /f /v DynamicDaylightTimeDisabled /t REG_DWORD /d "1"