I'm looking for suggestions to either fix or further diagnose an audio problem I'm having. The components involved are a Mac Mini (Late 2012) running 10.13.6 and a Focusrite Scarlett 18i8 USB audio interface.
Starting two days ago, audio output would stop after some amount of playback, ranging from a few seconds to 10 minutes. While playback is broken, recording has been working correctly. The system has had no software upgrades or installations in the past few weeks.
Switching the Scarlett to a different USB port caused everything to start working again temporarily. When it failed on the new port, switching back to the original also worked temporarily.
Suggested fixes such as trashing audio preferences and doing a SMC reset have had no effect.
Attaching the Scarlett to an obsolete MacBook Pro (Mid 2009) running 10.11.6 doesn't seem to produce any problems.
EDIT:
I was able to update to Mojave (thereby avoiding the Catalina trauma) but it resulted in no change to the symptoms.
Best Answer
I had a similar issue on High Sierra with a Line6 interface; slightly different as the audio would fail if I left the machine alone for a while. It didn't sleep, my machines never do, but after some unknown period of time the audio would fail.
When it did this it would also cause any video to fail too - endlessly spinning pizza wheel when on VLC or YouTube etc.
My temporary fix at the time was to toggle my output's output frequency in Audio MIDI Setup, 44.1 to 48 & back again [or vice versa] which would be fine for another day or so.
The issue went away with Mojave [as did many other issues High Sierra was plagued with].