Windows Server Update Service and SVCHOST running at 99% of CPU

Well, this is a real big one, just about everyone who is running a big network and using WSUS will know about this one. Today I had numerous calls from users about their PCs running slowly. Probably this has just happened since I got time Monday to sit down with WSUS and make sure all the updates were approved for installation (Since we reinstalled WSUS on a member server that had been turned into a DC, some of the older updates were not approved for installation). But some of our users have been reporting this problem since mid April.

Basically SVCHOST.EXE is running the automatic updates scan, while this is pretty normal, it’s said there are some bugs in the Windows Update Agent and other bits that are causing this problem. If your PC is idle or working normally, type wuauclt /detectnow at a command prompt or using the Run command from the Start menu and you will see it happen pretty quickly. SVCHOST.EXE will have an instance visible in Task Manager that is using maybe 50,000 – 100,000 KB of memory and high CPU utilisation.

There are several fixes depending on circumstances. Microsoft has said the patches will be released to WSUS on 22 May. The major one is the WSUS 3.0 Client Agent. If you want to download and install this manually on your PCs I recommend you create a restore point first. There will also be the WSUS 3.0 Server coming out in a few months which will also improve the situation.