Tip date: August 14, 2010
On the second Tuesday of every month, Microsoft issues a regularly-scheduled set of security patches, and within the next couple of days almost a billion computers reboot automatically overnight. The reason? When Windows Update installs certain types of updates, a reboot is required so that certain software components can be updated while they're not running. Unfortunately, this means that many people will leave their PCs running, with open applications and unsaved data, and in many cases, they'll wake up the next day to discover the PC was automatically rebooted by Windows Update. And sometimes, data loss can occur.
I firmly believe that the benefits of letting Windows Update automatically update your PC far outweigh the negatives, and while detractors will point to those few times where an automatic update actually did cause a problem, those are the exception not the rule. But like many of you, I've been burned by the automatic rebooting, and have woken up only to discover that an in-progress article or other document wasn't properly saved when Windows Update did its thing.
If you'd like to prevent this behavior, there are two things you can do. First, you can configure Windows Update to download but not install updates automatically. To do so, navigate to Windows Update, Change Settings and choose "Download updates but let me choose whether to install them" from the "Important updates" drop-down list.
Or, you can follow the steps below to prevent Windows Update from rebooting the PC while you're logged on. It will still automatically download and install updates--assuming you've configured Windows Update that way--but it won't reboot the computer.
Here's how:
First, run the Registry Editor (Start Menu Search, regedit) and navigate to the following key (in Regedit, Registry keys look like folders):
HKEY_LOCAL_MACHINE\SOFTWARE\Polices\Microsoft\Windows
Right-click the Windows key (folder) and choose New and then Key. Change the new key's name to WindowsUpdate and tap Enter.
Then, right-click on the new WindowsUpdate key and choose New and then Key. Change the new key's name to AU and tap Enter.
Now, right-click on the AU key and choose New and then DWORD (32-bit) Value. Change the new value's name to NoAutoRebootWithLoggedOnUsers and tap Enter.
Right-click the NoAutoRebootWithLoggedOnUsers key and choose Modify. In the Edit DWORD (32-bit) Value dialog that appears, change the Value data field to 1. Click OK to close the dialog.
Close Regedit and, for irony purposes, reboot the computer.