We may never know the true reason for this slowdown (it does not happen on Windows 8.1 or Windows 10), but over the past few months, Microsoft has released several patches that, combined, restore the faster scanning speeds Windows 7 used to enjoy in years past.
I credit Woody Leonhard for collecting this info in two articles: This one and this one. Below are some quick steps for downloading and installing these patches so you can restore your Windows Update performance. For more information (and a number of other handy Windows Update troubleshooting steps), check out topic #17 at my GWX Control Panel Troubleshooting Guide.
Thanks also to commenter Chuck for suggesting an additional patch for addressing the issue.
- Before you start, restart your computer- this puts Windows Update into a fresh state where it isn't busy working on background tasks. (You won't be able to install the following patches if Windows Update is busy in the background.)
- For each of the following links, download the correct version of the listed patch for your specific version of Windows 7 (32-bit/x86 vs. 64-bit/x64, etc), then install the patch, and finally restart Windows if you are prompted to do so. This bypasses having to get the updates via super-slow Windows Update, which is the problem we're trying to fix!
Over time, specific Windows Update patches can be superceded by others. Just download the updates Microsoft recommends instead if this happens. (And let me know so I can update my links!)
- The next time you run Windows Update you should experience improved performance. If you still encounter issues, please check out topic #17 of the GWX Control Panel Troubleshooting Guide for more steps.