I'm not sure if somebody else had this problem before, but for me this keeps happening every couple of weeks. It happened for the third time recently. Out of the blue on shutdown Windows says that it's installing updates with the typical counter of percent complete going up. This is weird for a couple of reasons. First, no new updates were available. Second, the updates are configured to be confirmed, so they cannot be applied automatically. I have confirmed in the update history that indeed no update was installed at that time. So, on the next startup Windows finishes installing fictional updates again with the typical counter going up until it reaches 100% and then the message is displayed that Windows Update Cleanup is taking place (or something to that tune - I don't remember the exact message). This step takes considerable time, I'd say at least 15 minutes with heavy disk I/O. Then when I'm finally able to login the CPU spikes with TrustedInstaller hogging one CPU core. When TrustedInstaller finally is done with its thing (a long time, 2 hours or so) I get a pop up balloon saying that new updates are available. The problem is the "new" updates are quite old and I'm positive that they were installed before. Previously it was .NET framework fixpak or something like that, and this time they are some security updates, one of them even dating back to 2012. If I let the updates to be applied the same set of updates will be displayed again and again. There is no way of getting out of this vicious cycle. Obviously, Windows Update stores keep getting corrupt, but my question is why Windows keeps doing this to itself? The Windows application error log has lots of informational events 1001 WindowsWcpOtherFailure3 pointing to Windows::Rtl::SystemImplementation:: DirectRegistryProvider::SysOpenKey API call (I assume). There are more details in those events, but I don't think those details are very relevant here. Is there a way to restore just the WU stores from backup? What I've been doing so far was to restore the whole partition from the latest image (taken monthly) and then restore all the user data from backups, but this is extremely tedious and time consuming process, and it seems to be only a temporary fix, as like I said this keeps happening every couple of weeks and there is no reason to believe that it won't happen again. I'd appreciate all the suggestions as to why is this happening and how to fix the issue without resorting to complete partition restore and then restoring the user data.