svchost.exe causing 99% – 100% CPU usage, solution follows

Update March 5, 2007: Microsoft has apparently released a patch for this issue available publicly at KB article Q927891. This specific article exactly describes the issue I had with a client’s computer. I backtracked a few referral links to this post and noticed the discussion on Ars Technica’s forums. Thanks to people there for following up on this.

Quick note for the tech-savvy: I’ve been reinstalling several systems lately for clients, and here’s something to check on your own boxes if you’re having strange stalling or CPU usage problems.

This problem typically occurs under these circumstances:

  • You have Windows 2000, XP or 2003 Server installed on your system (I’m not sure if Vista is affected)
  • You’ve installed Microsoft Update as the Windows Update page recommends
  • You have a copy of Microsoft Office 2003 or any Office 2003 applications installed (this could affect previous versions, too)

If your CPU usage is randomly spiking to 99% or 100% with a svchost.exe instance, download Process Explorer and look for the svchost.exe instance that’s pegging your machine’s processor. If, when you expand the process, you see “wuauclt.exe” or a Windows Update thread running, your problem is related to this bug.

Microsoft does have a KB article about this issue (927891) and it’s been mentioned by a few Microsoft MVP’s – here’s how you go about getting the official hotfix. If you don’t want to go through all that rigamarole, I’ll be calling in this week to acquire the hotfix for some of my clients experiencing this issue.

Alternatively, to fix it RIGHT DAMN QUICK NOW? Hit the jump.

Disable Microsoft Update

  1. Start Microsoft Update (Tools > Windows Update from Internet Explorer), then click the Change settings button on the left.
  2. Select the Disable Microsoft Update software and let me use Windows Update only checkbox and click Apply changes now.
  3. Reboot your system.

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