It may be a background process clash, and one of them either doesn't want to play ball or doesn't start up/shut down properly,
or some program has replaced a driver or file or whatever,
or an anti-malware or security thing has jacked or quarantined a file or driver thingie
Perhaps some trial betrayware or software install or uninstall went south a while back and everything has been half snafu till now
An MS file in the update process may be an MS security threat...
etc etc etc or it may be a combination of the above at random causing the update fail
Either way, the update loop isn't going away on its own, so it's time to get medieval and either remove and add hardware (PITA)
or lower the risk of paper cuts, lost screws, badly reseated cards, ram, processors and lab rage
by simply cloning the drive and trying it elsewhere