I think this is repeatable, thus it may be fixable:
Open a project in Dorico.
Open Layout Options (Shift+Command+L).
Open another Dorico project from the Finder.
(Moral of the story: don’t open another project while the Layout Options dialog is open.)
When I do that Dorico hangs. And then I have to reinstall NotePerformer and restart the computer for it to regain usability.
I don’t think this causes a problem in general. I’ve just tried it myself with no ill-effects, for example.
You won’t need to reinstall NotePerformer to recover your equilibrium. If Dorico hangs, use the Force Quit Applications window to quit the Dorico process, then run Activity Monitor and find the VST Audio Engine process in there, and quit that too.
Then wait a few seconds, and start Dorico again. It should start right up, and everything should be fine.
Yep, I forgot that. I think I had previously partially learned that I could quit the VST Audio Engine process(es) in Activity Monitor.
BTW, I did not even need a response, and you responded before the pixels were dry (mixing metaphors). Thanks for amazing customer service!