In my case, the machine recovered on its own. Here’s what I observed:
Happened to go past the room where that machine is located, noticed that the Window startup screen was effectively frozen - no spinning dots indicating startup, just the Windows logo on the screen. Moved the mouse, but got no cursor. Hit reset and initiated reboot. Got to the same point and froze again.
Did another reset. With Windows 10, a couple of failed boot attempts will summon up an automatic repair routine that checks and attempts to correct startup problems. In this case, it detected the failed update and undid the changes made by the update.
Had this failed, I would have restored a backup image of an earlier build to my hard drive using Macrium Reflect Free.
Thank you. Very good to know.