Windows Update doesn't work and consumes 100% of CPU (Win7 SP1)
Fix
Microsoft released a Windows Update Client Update which is part of the July 2016 Update Rollup to fix the long hang at Windows Update scan.
This update contains some improvements to Windows Update Client in Windows 7 Service Pack 1 (SP1). This includes the following:
- An optimization that addresses long scan time for updates that's reported on some computers.
Download:
32 Bit
64 Bit
Stop Windows Update service. This speeds up the setup of MSU updates. This can be done from the command line, or from the service manager window.
Try the downloaded update and see if it speeds up the installation of Updates.
To be able to install the update you first need to install the April 2015 servicing stack update for Windows 7 and Windows Server 2008 R2 update (again, stop WU service before trying to install the MSU).
Download (April 2015 servicing stack update):
32 Bit
64 Bit
Workaround 1
If this is still not helping to search for new updates, use WSUSOffline to get all the updates.
After one day trying to solve this problem I've created other Virtual Machine to check if the problem could happen again.
Unfortunately, the problem happened again! After that I've talked about this issue with a friend and he suggested me to disable IPv6 of my Windows network interface. I did it and two behaviours were observed:
On the new virtual machine when I disabled the IPv6 the consume of CPU dropped almost instantly and the Windows Updated worked as expected.
On the other virtual machine the consume of CPU hasn't dropped after disabling IPv6. After observing that I restarted the Windows and the consume of CPU remained high. However, after 30 minutes (about), the consume of CPU dropped and everything worked as expected.
Both Windows were successfully updated after disabling IPv6.
It's important to note that I can reproduce this behaviour. I have copies of my Virtual Machine before disabling IPv6.
Something else that may help is the Windows Update Troubleshooter - it's a standalone application that can diagnose problems with Windows Update and the Background Intelligent Transfer Service (BITS).