I’ve got the same issue too. New Mac Book Pro 13 2020 with stock macOS Catalina installed and today’s connection fail.
The DSPMIXFX detects and can interact with my UR242 but since I stated it it disappearing from system audio devices and when I try to start Garage Band too. Do you have any solutions?
Dear Steinberg/Yamaha! Why you ignoring our messages about this issue?