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Windows Update and Automatic Reboots

Windows Update and Automatic Reboots

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Windows Update plays an essential role in keeping your computer safe, and in order to do that, it sometimes has to reboot your computer.  In this blog post, we want to help clarify how WU reboots your machine (including key differences between XP and Vista behavior), why it does it, and how you can change your WU settings to better fit your needs.

Automatic Rebooting

The goal of Windows Update is to always keep your computer as safe and secure as possible.  Therefore, if you decided that Windows Update should Install updates automatically, an automatic system reboot may be a part of the process.  Choosing any other option will disable automatic reboots, but we do recommend that you keep automatic updates enabled!

Windows Update change settings control panel

Why does Windows Update sometime require a reboot?  Well, some updates require access to files currently in use by your system.  Windows Update does not know if or when those files will be available to use, so your system requires a reboot to avoid any conflicts. For security-related updates, your computer is unsafe before that reboot occurs: it is vulnerable to attacks which exploit the issue(s) fixed by the update requiring a reboot.  

For that reason, when Windows Update automatically installs an update that needs a reboot, it proceeds with an automatic reboot.  In order to make the updating process more convenient for you by preventing disruptions to your work, WU defaults to installing updates (and subsequently rebooting your computer) at 3:00AM.  Additionally, if updates are installed while you happen to be using the computer, and a reboot is required, Windows Update notifies you with this dialog:

Automatic reboot dialog 

The center countdown timer  starts at 5 minutes.  You can Restart now, or Postpone the reminder by 10 minutes, 1 hour, or 4 hours (In Windows XP, you can postpone for 10 minutes).  

There is one exception – a system administrator can deny your rebooting privileges.  For user accounts without rebooting privileges, Windows Update disables the Restart now button.  You can still Postpone, or your system will automatically reboot after 5 minutes.

Update Deadlines

A system administrator can configure some computers behind a Windows Server Update Services (WSUS) server with update deadlines.  When reaching a deadline, Windows Update begins an automatic install of those updates based on settings determined by the system administrator.

This deadline-based automatic install behaves identically to a Windows Update automatic install.  Therefore, if one or more of the deadline updates requires a reboot, Windows Update presents the same dialog box to you with the same options and conditions.  However, if a deadline update requires a reboot, then the reboot cannot be postponed – the Postpone button in the dialog will be disabled.

Policies to Change Automatic Rebooting Behavior

Two group policies allow you to configure how Windows Update handles automatic reboots.  In order to edit these policies, you must own Windows XP Professional, Windows Vista Business, or Windows Vista Ultimate.  The Group Policy Editor is not available in Home Windows versions.

To use the Group Policy Editor, follow these directions for both Windows XP and Windows Vista:

In Windows Vista, there is another way to access the Group Policy Editor:

·         Click Start

·         Select Control Panel

·         Type Group Policy into the search box

·         Click Edit Group Policy, the only result that appears


Once inside the Group Policy Editor:

·         Expand Local Computer Policy

·         Expand Computer Configuration

·         Expand Administrative Templates

·         Expand Windows Components

·         Finally, select Windows Update.

The Group Policy Editor with related Windows Update policies looks like this:

Group Policy editor 


With Automatic Updates enabled, the two following policies help you configure automatic reboot behavior.

No auto-restart with logged on users for scheduled automatic updates installations

If you set this policy to Enabled, then your system will never automatically reboot when a user is logged on to it.  After Windows Update automatically installs updates that require a reboot, it presents all logged-on users with the following dialog box:

Pending reboot reminder 

With this policy Enabled, Windows Update never automatically reboots your system, so there is no 5 minute timer.  You can Restart now, or Postpone the reminder by 10 minutes, 1 hour, or 4 hours (In Windows XP, you can postpone for 10 minutes).

Not Configured is the default policy setting and uses the 5 minute timer.  Disabled works identically to the Not Configured setting.


 Delay Restart for scheduled installations

This policy allows you to change the initial timer for automatic reboots.  If you set this policy to Disabled or Not Configured, the default setting, then Windows Update uses the default wait time of 5 minutes.  However, if you set the policy to Enabled, it asks you to enter a number which sets the initial wait time. 

For example, if you set the number to 15, Windows Update presents the following dialog after it finishes automatically installing an update that requires a reboot:

Modified countdown timer

Notice how the text following “Restarting in: began with a 15 minute timer instead of a 5 minute timer.  Other behavior remains the same.


There are a lot of tools available to help you set up Windows Update to act how you want it to.  We hope that this blog post will help you to do so!  If you want some more in-depth detail about how Windows Update works, the Microsoft Update team just posted a white paper on TechNet.

We’ll be paying attention to your comments, so please give us your feedback!


-WU Client Team

  • Great Post!  If anyone had any gaps in the AU process and behavior, this closed them!  Keep these kind of articles coming!  

  • I left my machine for an automatic reboot.  But when I returned it was hung on the shutdown screen.  After I turned it off then on, it won't complete the boot cycle. It hangs when doing the chip test.

    Is there a part of the update cycle that can fry my chips?  My first guess is that one of my memory sticks is fried... I hope.  It could be worse.

  • What is the interaction between Update Deadlines and the "No auto-restart with logged on users..." group policy setting? Is the deadline ignored? Can the user put off the reboot indefinitely?

  • Try here, fixed for me;

  • Great post, exactly what I was looking for. I couldn't find the delay restart for scheduled installations.

  • This question may relate to Mrith's question above...

    Is there a difference between the computer configuration setting for windows update if it is stated as...

    A>>>>>"No auto-restart with logged on users for scheduled automatic updates installations..." There are 15 selections here compared to 11 in the below gpedit.msc why?

    Compared to...

    B>>>>>'No auto-restart for scheduled automatic updates installations"?????????????

    Regardless if the later system with the gpedit.msc setting is enabled the system still seems to reboot.


    1.) is there a difference between the two statements A and B?

    2.) why are they different? both systems are XP V. 2002 sp3

    3.) I have read that this "no auto restart" is over-ridden if there is a "deadline" set. Is this the case?

    4.) If so where is this deadline set?

    I have users that regardless of our request shut machines down and therefore don't get updates.

    But, they are running scientific research devices that when are automatically shut down have the potential to loose Irrecoverable data. This is an unacceptable situation.

    How can I stop this from occuring? Aside from getting my users to keep there systems up at 3am on sunday?

  • Please respond to and for the above questions.


  • Great post! I have founded answers to my problems with Group policy editor. Thy for this post once again!

  • oops, just set up a new Vista Home Premium system and enabled automatic updates.  And this morning I see my system was rebooted and several pieces of in-progress work were lost.

    IMO this is totally unacceptable behaviour.  Losing customer data is a critical defect!  I see from this post that I can purchase an OS upgrade in order to override this behaviour.  Thanks, Microsoft.

    I will work around this defect by disabling automatic installation.  But that won't bring back my lost work.  :-(

  • 242 Microsoft Team blogs searched, 118 blogs have new articles in the past 7 days. 314 new articles found

  • I last updated my windows xp operating system no problem at this time also thank you for the information provided

  • windows xp auto update itself to be very useful to make.

  • Thank you for sharing such a beautiful presentation and explanation will follow your blog every day I thank you again

  • was a very good explanation, thank you and have a useful information

  • expression and picture your expression was very beautiful about how little I thank you thank you

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