High Sierra - The path /System/Installation/Packages/OSInstall.mpkg appears to be missing or damaged Got the following error 


  The path /System/Installation/Packages/OSInstall.mpkg appears to be
  missing or damaged


while upgrading Mac Mini (Late 2012) to High Sierra. The only option on the screen is to restart, after which the same error pops up. Tried some suggestions from google search and none of it is working


Tried booting to recovery and using disk utility to repair/firstaid
   but disk utility is struck in discovering state spinner for one hour
Using terminal in recovery mode to check the disk and repair permissions and SMART status all are reported fine
Tried diagnostics and it reported all good
Internet recovery stuck at globe 3:30 remaining time for past 5 hours
Tried booting to safe mode which is stuck at apple logo for past 7 hours


What is the next setup in this case, I have Time Machine backup but it was 1 week old and there are some important unbacked files that I cannot afford to lose
Same error happened to me when I received an update from 10.13.1 to 10.13.2.

If you boot with shift button pressed, you will be able to enter safe mode and try to download and reinstall an update.
It did not help to me so I booted holding Option key and chosen regular Mac HD (not an update volume). Booted to my Mac without safe mode and tried to reinstall this update. Somehow it worked out in several reboots.