We've just had a Windows 8.1 Lenovo laptop that stopped booting. It reported attempting Automatic Repair and kept failing and rebooting through the same cycle.
The advanced options after that has failed also gave you you a startup repair option. That wasn't able to fix the fault either.
The error reported was Total identified Windows Installations: 0
In the end the fix was from the command prompt option, but we had to go into C:\Windows\System32\Config and rename the registry files (Default, Sam, Security, Software, System), eg. default.bak. Then copy the replacement files from the Regback subfolder where there is a recent backup.
The laptop rebooted with no bootrec tweaking needed.
NOTE - Looks like since Windows 10 version 1803, Microsoft are no longer creating a backup in Regback. You can still recover registry files from a Shadow Copy. See this article for details https://theitbros.com/restore-windows-10-registry-from-backup-or-restore-point/