Can not relaunch without immediate crash on loading!
This behavior immediately followed an instant crash when: Preferences > Keyboard > Touch Bar > Show Tool Palette in Touch Bar (toggled on).
Crash reported to McNeel with file. Works in MacRhino R7. Not sure if reinstall is the only solution here?
(BTW: The TouchBar tool palettes are a truly awesome feature when working – especially for Gumball use)