Cubase 11 Pro suddenly stopped my Windows system audio from working

Thanks for that. Yes, Cubase works fine, it outputs sound to the UR242 without problem.

The problem is that the rest of my Windows system - i.e. any other programs, apps or system sounds - will then have no sound until I reboot.

I.E. There will be no sound from VLC player, Spotify, YouTube, etc (YouTube will no longer even play videos, it just has a spinning wheel and a message that I should restart my system if playback doesn’t work).

Worse; even after I shut down Cubase, my Windows system won’t play any sound, until I restart.

Once I restart, my system will have sound and work fine (e.g. I can play YouTube videos), until I start Cubase. Then I’ll only have sound in Cubase until I reboot my system.