I have a fresh installed computer with Windows 7, 64-bit, Service Pack 1.

After a few minutes after startup, svchost.exe is consuming 100% of one cpu core.

I know there are many threads which are dealing with this problem, but none of them helped me.

I installed this updates: KB3050265 and KB3065987

I used this "Microsoft Fix it"-Tools: MicrosoftFixit50123 and MicrosoftFixit50362

I installed the current Windows Update Agent: https://support.microsoft.com/de-de/kb/949104

I tried to remove the SoftwareDistribution directory:

net stop wuauserv
net stop bits
rd /s /q %windir%\softwaredistribution
net start bits
net start wuauserv
wuauclt.exe /detectnow

And I tried to connect the computer with my home network over a usb/ethernet-adapter, and I tried to disable IPv6.

For diagnostic, I post here the WindowsUpdate.log file (after removing the SoftwareDistribution Directory, waiting until the service is hanging on 100%): http://pastebin.com/ZisR9Pft

  • Install Process Explorer, click the process name column until you get the tree representation, then find the instance of svchost.exe that is looping. Examine that process's tree to find the actual module involved -- often this is not a Windows module but some other application. – Daniel R Hicks Aug 16 '15 at 12:23
  • I updated the link to the WindowsUpdate.log (I missed a bit), and here are screenshots from process explorer – A. Fendt Aug 16 '15 at 12:31
  • Change the display options to make the "command line" column visible and see what the command line is. – Daniel R Hicks Aug 16 '15 at 12:34
  • Here we go. – A. Fendt Aug 16 '15 at 12:38
  • If you Google "svchost netsvcs" you will get a mountain of advertising interspersed with the occasional suggestion on how to approach this. – Daniel R Hicks Aug 16 '15 at 12:48

The CPU usage comes from Windows Updates which tries to find Updates: wuaueng.dll!CAgentUpdateManager::FindUpdates. This method calls a function wuaueng.dll!CUpdatesToPruneList::AddSupersedenceInfoIfNeeded to see if all updates are needed or if they are replaced (superseded). And this takes some time on your older Intel Core2 Duo CPU. You can't avoid the CPU usage. For a fresh Windows 7 install, use other tools that provide the current Updates.

// Update

Microsoft released a new WindowsUpdate Client Update to fix the slow Update searching/Installation.

Installing and searching for updates is slow and high CPU usage occurs in Windows 7

32Bit: http://www.microsoft.com/downloads/details.aspx?FamilyId=fcd6bf5d-f004-4ca3-aa7e-1de462b91dd0

64Bit: http://www.microsoft.com/downloads/details.aspx?FamilyId=4fe566bd-31b1-4413-8c4c-412b52533669

Also try if this improves your situation.

  • Now I waited four hours and svchost.exe is still running on 100% cpu. I created a second trace after this time, here ist the download link. The Method wuaueng.dll!CUpdatesToPruneList::AddSupersedenceInfoIfNeeded was called over 1700 times. I can't use wsusoffline, wsusoffline is using wusa.exe to install the updates and wusa.exe is waiting until all wuauserv is finished searching for new updates. – A. Fendt Aug 17 '15 at 15:48
  • I use a small batch file where I stop wuauserv before installing the next update. This improves install a lot. – magicandre1981 Aug 17 '15 at 16:01
  • KB3102810 was released to address this. – aoetalks Nov 11 '15 at 21:29
  • still getting svchost of wuauserv going to 50% (100% if it was only one cpu core, bieng single threaded on a dual core it shows as 50%) even after installing KB3102810 on windows 7 ultimate 32bit – Costin Gușă Jan 30 '16 at 15:38

I tried everything you did as well. What finally fixed it was this answer; I installed KB3102810 which was recently released and it worked for me on 2 different machines.


Very important: It is normal that Windows Update uses full CPU (e.g. 50%) for a very long time. I just spent many days trying everything possible, always stopping the update after giving up at ~3 hours of waiting. But in the end the solution was to simply wait for longer. I can confirm that a first time Windows Update can nowadays be stuck on the Checking for updates screen for at least 4 hours, while CPU is peaking and nothing else happens (except for the progress bar looping animation). This on a 2009 computer. On older computers it can probably something like 10 hours even. Most unbelievable thing ever. (And this has absolutely nothing to do with network problems, by the way.)

  • 2
    No, it is not normal. It is exceptional. – David Balažic Nov 25 '15 at 14:15
  • I have just had a production server fall over because there was insufficient CPU time to dedicate to its main job, with wuaueng.dll consuming everything on one core for several hours. Even if this is normal, it is not acceptable. We have had to turn off update checking altogether for now. – Calchas Mar 11 '16 at 9:37
  • After experiencing many hours waiting time on several completely different computers and setups, I would still say that it is "normal". Though on my latest computer it wasn't 50% or 100% of CPU usage but rather something like 18% (svchost.exe). In any case, it took many hours and looked exactly like Windows Update (and actually a similar other Windows update dependent update too) wasn't working at all. It adds to the confusion if Windows Update says Never updated. It feels like it is completely broken but might only be VERY slow. – Jim Hoyle Apr 20 '16 at 19:24
  • After two years, I think I have to dispute my own previous comment. I now completely started from 0 with the computer in question. This time, after doing a full format, the Windows Update worked much better. Another symptom was before that System PID 4 ran forever with high disk usage all the time or often. That led me to find out that there might've been something wrong with the hard drive all that time. But now, after a full format, it works better. – Jim Hoyle Aug 28 '18 at 6:45

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