After trying just about every solution I could find I was able to resolve the problem. I also noticed that Spotlight was not working as expected. Typing Disk for example did not find the Disk Utility APP - just web search links. It was my suspicion that something was cached that could not complete somehow and this held up a shutdown? I found some instructions to use Command Line instructions to clear. After running these my MBP was able to shutdown/restart. Following this (just for truing up) I installed the 10.13.6 combo update. All is well now.
Here is what I did (from How to fix a Mac that won’t shut down)
After opening terminal, type all the following commands in the window, one-by-one in execution.
- rm -rf ~/Library/Caches/*
- rm -rf ~/Library/Saved\ Application\ State/*
- sudo rm -rf /Library/Caches/*
- sudo rm -rf /System/Library/Caches/*
- atsutil databases -removeUser
- sudo atsutil databases -remove
- sudo atsutil server -shutdown
- sudo atsutil server -ping
- sudo rm -rf /var/folders/*
Once you performed the last line, restart your Mac.
Following this the shutdown happened. The Spotlight rebuilt and now works as before. Seems like I have been able to save wiping SSD, reinstall and restore! As always your milage may vary.