I. too, fell for Microsoft's trick.
My computer became dead as a brick.

Nothing I tried would repair it.
Just as I was about to despair, it

dawned on me, to not spoil my supper,
I'd better run AOMEI Backupper.

The image I used was a week old.
Now my computer's again good as gold.

The end. - at least until KB4103721 arrives again.

Of course, Microsoft in all their wisdom wiped out all daily
system restore points.

Jim.


EDIT: https://www.windowslatest.com/2018/05/09/windows-10-kb4103721-bugs/