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Automatic Update causes SVCHOST.exe high CPU

Automatic Update causes SVCHOST.exe high CPU

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SVCHOST high CPU.  If stopping  the Automatic Update service, the high CPU issue disappears.


You can use the following method to verify whether it is AU caused SVCHOST high CPU.


1.       Run the command to find the PID of SVCHOST which is running on Automatic Update service.

Tasklist –m wuaueng.dll


2.       Run the command to enforce client to Automatic Update.  In certain circumstances, high CPU issue may recur after running the command.

Wuauclt /detectnow


3.       Find the PID of SVCHOST which is running on Automatic Update service, monitor and verify if it causes high CPU for long time. High CPU for short time is normal and is not a problem.




If Automatic Update causes SVCHOST.exe high CPU, please refer to the following KB articles:


You can try the following methods to resolve the issue.


1.       Install update KB927891


2.       If client still encounters persistent 100%CPU issue after installing update KB927891, please download and install the latest WSUS 3.0 client:


32-bit versions


64-bit version


The 2 updates (KB927891and WUA3.0 )to resolve AU related SVCHOST high CPU issue are available on WSUS now.


KB927891 is available on WindowsUpdate /WSUS. It is listed as Critical Updates in WSUS. Please refer to:


KB936301 is listed in WSUS as Critical Updates. It is to install on WSUS 2.0 SP1 server to upgrade Selfupdate tree to “WSUS 3.0” but keep the server as WSUS 2.0, so that client can get WUA3.0 by visiting WSUS selfupdate tree. Please refer to:


Based on our monitoring and customers’ feedback, the above two steps are able to alleviate the Issue.


For the latest update about the issue, please refer to the following web site.


If you have any question about the issue, please contact GCR PSS Security Support Group ( to get further technical support.

 [v1]Is this supposed to be here?

  • Tried both patches with no success.  The only way I was able to get Windows Update to work was to reset my display driver to absolute minimum (640x480 - 16 colors).  The updates ran fine.  I haven't had a chance yet to reset the resolution to something real to see if it still works.  Maybe something changed in your scrolling green bar?

  • I have found that either sometimes a computer has to stay on overnight before it will complete the scanning process. This is possibly due to either certain older (non dual-core) systems can't cope with the massive CPU load that is generated by svchost.exe or the WSUS service can't cope with more than a few client requests at once. Either way it takes on average 2 days to get a Windows XP system updated from a basic SP2 install... quite annoying since the users here expect a turnaround time of a few hours!

  • Tried them all still the same issue.

    This seems to be caused by updating from WSUS 3.0 to WSUS 3.0 SP1.

    I have got some machines working killing all the update services processes and Deleting %windir%\SoftwareDistribution, %windir%\System32\SoftwareDistribution, %windir%\System32\CatRoot and %windir%\System32\CatRoot2

    Ran the WindowsUpdateAgent30-x86.exe

    After the installation ran "wuauclt /detectnow"

    Let me know if there is a better solution for this....

  • I ran the KB927891and WUA3.0 but the problem remained, although better thanit was. Tom's solution clearing out %windir%\SoftwareDistribution fixed the issue.  However, the cause is not clear.  In this case an update to the Genuine Windows Validation tool had occurred about 3 days before the issue started. On the 3rd day a Windows update was flagged to be installed on shutdown, which it was. On next boot the problem started.  My client's other PC had the same Genuine Windows Validation tool update applied about a week later, and it too developed the problem 3 days later (ie a week after the first PC).

  • Further to my earlier post I have now confirmed that the SVCHOST/update high CPU problem was caused by installing the Office 2007 converter pack which, on next boot, caused Office 2007 patch KB947801 to be installed. The high CPU use stared on next boot.  This process has been followed on a second PC with the same result.

  • I also used Tom's solution to correct this annoying problem.  I am running Windows XP Professional with SP2 and all current updates as of 5/23/08.

    Thanks for the info Tom. Now to fix the rest of the PCs having this problem.  One thing I noticed is that it's only happening to my Intel based systems. AMD doesn't seem to be affected though I don't know if that has anything to do with it.

  • Thank you for you superior work!  You really put your heart into this and IT!

    I am running all soultions now!

    Best Regards

  • This was happening for me with Auto and Manual updates for "Windows XP Mode" (virtual windows xp on windows 7. I tried everything I could find documented on fixing the issue to no avail. Upgrading IE 6 to IE 8 seems to have done the trick, now manual updates is actually working! Haven't thoroughly tested, but so far it seems promising :)

  • start--run--services.msc--automatic updates--properties--general--startup type.disabled--service status--stop--log on--profile1--disabled--ok

  • Jeff, you are awesome with that suggestion with WinXP in virtual mode. I have two machines that I have not updated in awhile and that was my holdup also with windows update just continuously running and never offering any updates! Downloaded ie8 from website after stopping automatic update service and once rebooted windows update now updating and installing updates, thanks!

  • Just turn-off the Windows Automatic Update

    --- Anyway Microsoft announced that their support foe WinXP will stop on April 2014

    --- by the way , even now 15-November-2013  their downloading for WinXP  is not working

  • Sure, lets just turn off automatic updates, uninstall Security Essentials, throw away thousands of dollars of our working software, convert our data and buy a new PC that can run Win H8TE and buy new software.  These are the kind of problems that you get when you let young people manage! This problem NEVER should have happened!!!  One day you have to reinstall your OS and suddenly you're screwed by the company you gave your money to. TOTALLY WRONG on so many levels!!!

  • The contact has been expired. This issue looks like something new with Windows Update. The WU team is looking into it. Suppose the fix will be in place soon.

  • I have been a customer of Microsoft since the first version of Windows came out 28 years ago.  I had planned to buy a new PC during this Black Friday weekend and move from Windows XP SP3 to Windows 8 but have changed my mind about doing anything until I see if the Windows Update team will fix this svchost.exe 99% CPU problem, which appeared in my Dell Dimension 3000 after automatic updates in October. (Since support for XP SP3 will end on April 8, 2014 my gut feeling is that Microsoft has done something nefarious to get a lot of people to do what I was about to do.)

  • I get the same issue with svchost running at 99% when I reloaded XP after slicking the disk.

    No other software on the disk except WinXP SP2, from the original install disk.  Tried running SP3 from a CD, still have problem.  Updated to IE 8, still have issues.

    Svchost runs at 99% of the CPU time.

    Cannot start or run the Firewall (or even start the service for it).  I think others have this issue but it may not be obvious.

    Have to turn off autoupdates or else svchost will eat up all of the cpu time, all of the time.

    Cannot run many Windows functions like IE because it will start a service host that will eat up all of the cpu time.

    Cannot run updater manually because once again, all cpu time is being eaten up.

    No viruses no malware. Have just reloaded directly from the original XP SP2 install disk.  SP3 did nothing to fix it.  Updating from IE6 to 8 changed nothing.  Loaded and ran both Security Essentials and malicious software removal tool and nothing both times.

    So the issue may not be an updater issue since mine is turned off.  Svchost at 99% fires up whenever I run IE8 or IE6 too.

    Also whatever it is, it prohibits me from being able to bring up the firewall or restarting the firewall service manually also.

    Like I said, that is not an obvious symptom, others may have that issue too but not know it.

    Whenever I run almost any program or function, it always fires up svchost and pegs it at 99%.

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