CEPHTML Engine

I keep getting a CEPHTML Engine has quite message across Illustrator, InDesign and Photoshop which sometimes throws me out of the program. This is REALLY annoying as it's disrupting workflow and sometimes can happen many times in a hour. Also I have various functions not working since the last update, one of which is that the Cmd-N command to create a new document in Illustrator no longer works and sometimes doesn't work in Photoshop either.

InDesign 13.1, Illustrator 22.1, Photoshop 19.1.2, MacOS 10.12.6 (currently, I will not entertain moving up to 10.13)