Remember how until recently microsoft was trying to force you to upgrade to windows 10 with all sorts of devious and underhand ploys? After the expiry of July 2016 free win10 upgrade deadline, "by coincidence" windows update on older platforms started playing up, eating up the CPU, failing to get updates, weird error messages like "error WindowsUpdate_80244019 WindowsUpdate_dt000". Please excuse my conspiracy theory paranoia but I cannot understand how such a basic component that supposedly keeps your PC in order can mess it up. I can understand failing to get updates, but getting stuck in a busy loop too? Eating up all the CPU? That's either mass programmer stupidity or simply a ploy to get people to upgrade!?
This happened to me the other day, both on my older windows 7 laptop, and on all my windows vista/7 virtual machines. Cooling fan overworking, CPU high, and no updates downloading (one can tell because nothing lands in C:\Windows\SoftwareDistribution\Download folder). I tried leaving it running to see if it would snap out of it, but it would be the same after hours of trials. Killing the faulty SVCHOST process wouldn't last for long because it would just relaunch itself. The only remedy was to disable automatic updates from control panel. But that's an unacceptable solution.
If you google for "windows update 100% cpu" you will find thousands of hits and will be overwhelmed by the amount of possible answers and fixes. I tried all of them I think, and nothing worked. And I am supposed to be a software professional. The supposed fixes are of three major types:
In the end of the day I resorted to microsoft's chat support (it's free for windows update problems). You have to allow the MS technician full access to your PC using remote assistance (LogMeIn), but you can see what they're doing at all times. First he tried out all the above "solutions" to no avail. Then he thought he'd nailed it and manually downloaded the updates KB3020369 and KB3172605. He gave me instructions to disable the update service, reboot then run the said KB updates. "I'm sure that will fix it" he said... which indeed happened but not as easily as I thought.
I already had the first update. The second (KB3172605) was added. Now what? I turned automatic updates back on. Again the dreaded CPU drain. Fek! Reboot, leave the damn thing to spend more electricity (very expensive in Cyprus :) and lo! 26 new updates available! I was almost in tears. Problem solved... for now.
I would say that this KB3172605 fix is possibly something specific to my x86 windows 7 system. So if you are stuck with a broken windows update service, please save your time, stop reading blog posts about the problem <g> and chat with a microsoft technician straight away!