Windows Update high CPU usage

Windows Update is acting odd today on my Win7 computer.

One svchost.exe process had high CPU usage (~50%) for a long time. Resource Monitor showed it was due to the wuauserv (Windows Update) service. At this point, I had no notification of any updates available in the Task Bar. Windows Update is configured to notify me that updates are available, but not to automatically download or install them. So there was no obvious reason for the service to be using a lot of CPU.

I rebooted, and the same thing happened again.

Then I opened Windows Update from the Control Panel, and it showed 26 important and 8 optional updates available. I clicked to download and install them (186.9 MB).

11 minutes later, the download progress was still showing 0% complete, so I clicked to stop it.

I tried restarting the Windows Update service from the Services panel, but got the message "Windows could not stop the Windows Update service on Local Computer. Error 1053: The service did not respond to the start or control request in a timely fashion".

I ended the offending svchost.exe process from Task Manager, and restarted the Windows Update service. I again clicked to download & install the updates.

Svchost/wuauserv started using a lot of CPU again.
50 minutes later, the download showed 3% complete - at least it finally was making progress. Another 80 minutes later, it finally finished and wants to reboot.

And now 15 minutes later without having rebooted yet, TrustedInstaller.exe has been using a lot (~50%) of CPU the whole time.

Hopefully after I reboot, the CPU usage will go back to normal.

If I ignored these things, they'd probably eventually complete on their own and not be issues. But it bothers me when background processes use a lot of resources, with no easy way for me to tell what is going on.

This person may be having the same problem, but I'm not sure.

Yep, after rebooting, walking away, and coming back to my computer a few hours later, it's back to normal.