After you install an important update in Windows 8 or in Windows Server 2012, you receive a notice that you have to restart the computer in three days. If the restart does not occur in three days, the computer displays a 15-minute countdown and then automatically restarts. By default, this automatic restart is delayed if the computer is locked, and the countdown will begin the next time that you sign in to the computer.
A new feature is now available that lets you force automatic restarts to finish installing important updates, regardless of whether you are at the computer. You can change to this new restart behavior through the following new registry key value that was introduced in the April 2013 cumulative update (2822241).
Registry subkey: HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU Value: AlwaysAutoRebootAtScheduledTime Type: REG_DWORD Value data: 0 (default value) or 1 (force a restart)
When this registry value is set to 1, you are still notified of the upcoming automatic restart on the sign-in screen. However, at the end of the two-day period, the 15-minute counter begins even if the computer is locked. The restart also occurs even if the computer is locked.
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 change the AlwaysAutoRebootAtScheduledTime registry key value to enable automatic Windows Update restarts, follow these steps:
Install Windows Update 2822241.
For more information about how to obtain this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:
2822241 Windows 8 and Windows Server 2012 cumulative update: April 2013
Start Registry Editor. To do this, follow these steps:
Swipe in from the right edge of the screen, and then tap Search. Or, if you are using a mouse, point to the lower-right corner of the screen, and then click Search.