Photoshop, Pemiere CC 2017 Won't open Macos Sierra, CEPHtmlEngine error message

What version of MacOS? What version of Photoshop? The first thing is to check if they are designed to work together.

if macs are not designed to work together with adobe then you might as well go back to the commodore 64.

macs and adobe are built for each other.

i would go down a different avenue of troubleshooting than that.

Try resetting the applications' Preferences, if you can't reset preferences within preferences do this:

Close and relaunch Photoshop, and IMMEDIATELY hold down Ctrl + Alt + Shift (Windows) or Cmd + Ctrl + Opt + Shift (Mac), and respond in the affirmative to the dialog asking if you really want to replace the preferences. you must be extremely fast on the keyboard (if you don’t see the confirmation prompt, you were too slow)

You may have to do it a couple of times before you get the hang of it!

If that doesn't work, uninstall the application(s), using the drop-down gear icon in the Creative Cloud app, run Adobe Cleaner Use the Creative Cloud Cleaner Tool to solve installation problems  before reinstalling the application(s).

Anthonycioppa, software is written and tested for specific versions of Mac OS. it is well known that there are incompatibilities between old (pre Sierra) software and Sierra. So the question about versions is absolutely vital.