Could you please let Jake Doe now that his post under:

How to fix Windows update error 0x800f0845 on Windows 10?

appears to be out of date, since Windows no longer shows “Startup Settings” in its “Advanced Options” Menu. I am also getting this Update failure of which he writes with the latest Windows Update KB4103721
(see http://support.microsoft.com/help/4103721) so it is appearing in more than one update (the article states it only appears solely for update KB4056892. I had to use (from the command prompt)
BCDEDIT /SET {DEFAULT} /BOOTSAFE NETWORK
in order to get the machine to boot in safe mode, and then it automatically uninstalls the faulty update. Perhaps a re-write of this article is needed. Just thought I would let you know.