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.