I'm using an old Mac mini and I'm having the same problem. from what I've read so far, from )S 10X 10.4 and higher (Im using 10.16.3 High Sierra/S15.2/AudioBox96/Atom/microKorg Air 32/Alesis SamplePad4)), should connect automatically without the need for UC Driver. However I need it for my Presonus ATOM. **The problem is that I don't see the AudioBox 96 as a choice to set as an Aggregator in Utilities' Midi Manager. Bottom line is that I've done everything from -unistalling UC Correctly to reinstalling to uninstalling again rebooting with complete shutdown each time with NO LUCK. very frustrating because I don't want to go back to my week PC. please share if something actually works.
**I have ticket in with support so if I find anything, my problem with my old Mac me be something all Macs need to do.