Looks like manually defining the Graphics API=OpenGL might have worked.
I made the change and locked my windows session then reopened it and the viewport is still there.
I test a few more times just to make sure, but I think this solved the issue.

Prior to setting the API, I did try resizing and minimize and maximize window, moving from one monitor to the other and it didn't resolve the black viewport.
So I am glad I the manual setting is working. Was getting annoying having to restart moi every time I walk away from my computer for more than 5 minutes.