I'm having a problem with my fireface UC. Logic can see it in its list of devices, but when I select it (and core audio is re initialized), no instruments or audio files will play at all. Not only will they not sound, but they will not even indicate any signal at the fader or the master output. Same with software instruments.

If I change to the built in output, boom, everything works normally. Change back, same issue. Also I notice the total mix software won't open properly (mixer window will not open). Can't get the Fireface USB settings app to open at all.

All this is on my mac mini, 10.15.3, with the latest driver, 3.19. Behavior is identical on my MacBook pro, 10.14.4. (I also notice the computers won't play any audio when the fireface is selected in audiomidi setup. any audio files just won't respond.)

I'm not sure what else to try. I've done a hard reset (hold in knob while powering up?). I've tried all usb ports on both machines.

this is a second hand unit I've just purchased. thanks. Darcy