Rhino 6 black screen during startup or opening file while on secondary (4K) monitor. Fine on primary display

HELP, PLEASE!

I was simply trying to create a keyboard short cut for the “polyline” command and now my rhino refuses to open any file, and even when I “create new file” it only shows black.

I have a Mac 2016 and have reinstalled Rhino 6 and nothing changed.

I am a grad student in architecture and in the middle of finals/review week. I’m distraught. This is terrible. PLease Help me RHINO!!!