Enable or Disable Windows Update Auto Restart

Stop and Disable Windows Update Auto Restart or Reboot

Auto-Restart dialog box

After downloading and installing an update from Windows Update, a window constantly pops up nagging you to restart, and even counting down to an automatic restart.
In Windows 7, Windows Vista and Windows XP, after installing downloaded updates via Windows Update manually or scheduled Automatic Updates automatically, the system will ask to auto-restart to apply all the updates.

Windows 7 has the option to allow users to postpone or delay the restart, the computer will still automatically reboot sometime later, if the updates required reboot to complete the installation.
If the system is has running an important task and cannot be restarted right now then you may stop rebooting after the updates are installed. You can change this feature of Auto-restart/Auto-reboot in group policy so that you will not be interrupted while working.

Local Group Policy Editor

Here are the procedure to enable / disable the auto-restart feature:
Group Policy setting:

1. Click Start -> Run
2. Enter “gpedit.msc”
3. Go to Local Computer Policy -> Computer Configuration -> Administrative Templates –> Windows Components -> Windows Update
4. Double-click on “No auto-restart for scheduled Automatic Update installation”
5. Disable or Enable it.
6. Reboot the computer.

No auto-restart for scheduled Automatic Update installation

You can also change the default setting of “Re-prompt for restart with scheduled installations” to remind you once a day, or so if you can still stand these pop-ups.

Re-prompt for restart with scheduled installations

Registry Editor setting:
This setting can be changed through registry with the following registry key and value.

1. Run Registry Editor (RegEdit). Type regedit in RUN box from start menu.
2. Go to Navigate to the following registry key: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\WindowsUpdate\AU
3. Change the NoAutoRebootWithLoggedOnUsers (If the key does not exist, create new one with this name) DWORD (32-bit) Value to 1 to disallow auto-reboot. By default, the value is 0 which allow auto-reboot.
4. Close registry editor.

When the policy is enabled, Automatic Updates will wait for the computer to be restarted by any user who is logged on, and not restart automatically. And Windows will not notify users that a restart is required to apply the updates.

Note:
This article is applicable for: Windows XP, Windows Server 2003, Vista, Server 2008,  Windows 7,  Server 2008 R2 and later.
References:
http://support.microsoft.com/kb/328010