I have encountered a problem of very long (better to say, endless) update search in a newly installed Windows 7 SP1 on one of the client computers. The problem looks like this: after the OS has been installed and the Internet connection has been configured, you go to Windows Update and run check for updates. The search lasts for several hours without any results, at the same time there is high CPU (up to 50-70%) and memory load by svchost.exe. The same problem can be seen in Windows Server 2008 R2 as well.
When analyzing running processes using Resource Monitor, you can see that wuauserv.exe service high load in svchost.exe process. This is the main process that is responsible for the operation of the Windows Update service.
The attempt to reset Windows Update Agent settings hasn’t given any results. Obviously, the issue relates to the changes on Windows Update site that prevent earlier wuauserv client versions from downloading the list of updates.
So if your Windows 7 stuck with the status ‘Checking For Updates‘ , try to manually download the update rollup for Windows 7 SP1/ Windows 2008 R2 issued in July 2016— KB3172605. Depending on the bitness of your OS, download a 32-bit or a 64-bit version of the update.
After the update installation, restart your computer and run check for Windows updates again. Voila — in some minutes you will see the list of more than 100 missing updates.