All cut, copy and paste functions quit
After an update by Apple of High Sierra all cut, copy and paste functions quit,
I did a reboot. No go.
I did a Safe Mode start up. No go.
Most of the online advice was either things I had tried or too darned technical for me and the average user to sort out.
Bottom line?
Reloaded High SIerra in its full glory solved it. Going into Time Machine was an option but all the data I had entered in the past 48 prior to the reload would have been lost.
Easy peasy. Wish I had just done it in the first place.
MacBook Pro, macOS High Sierra (10.13.3)