Setup a Dell PC for a neighbour two yrs ago. He now reports that it tries to install updates, then says failed, reverting changes. I had this on a laptop some time ago, but nothing I've tried is curing this PC.
I've tried installing the updates one at a time; some install OK, some fail on the first click then work on the second, others (those that need a restart) install OK and others give the dreaded 'reverting'.
I've looked at the update history and it suddenly started causing problems over a year ago. Again, since then, a few have been OK (mainly updates to defender and malicious removal tool), but most have failed.
I've run the update repair tool which says it finds problems but makes no difference.
Any thoughts before I throw myself off the nearest bridge?
"There are well over a hundred failed, so I shan't post them all!"
Hopefully you'll find that they all have the same failure code. I tackled the same problem a few days ago for a customer and fortunately for me they all failed with the same reason so implementing an effective fix was easy.
Have a look in Event Viewer for any relevant errors or warnings that occurred during the installation of the updates. Double-click on an event to view the full details. There's a "Copy" button there if you want to paste something here.
Hopefully you'll find some clues as to what's going on.