Mine was having the same issue. I had to power the laptop off, wait 30 seconds, then power it on 3 times. On the 3rd try, it booted into the login screen. The first 2 times it did the "restoring previous
version loop"... one thing I did do on the 3rd try (from complete shutdown), was pressed F8 like a mad man, but it actually shot it right to the login screen...
It worked with my Acer laptop too - shutting down by pressing the power button for several seconds, wait 2-3 minutes, then turning on and pressing F8 till it shows the login screen. You log in, all data is there (Google Chrome restored also all open tabs
before accepting the update) and it's shown a message that the update failed to install, but everything else is OK and the PC works as usual.
Thanks for sharing the first WORKING troubleshooting for this issue. <3
Microsoft, you should check this solution too and if you can not fix the update issue, please advice the customers to try it in order not to loose any personal unsaved data and not to have to reinstall Windows.