Hi there
I was sitting, naming outputs in Ableton, when my FireFace UC disappeared. The red host light is on - i've tried repeated in-and-outs  - also with several other macs (Yes - its a mac, on High Sierra - but i've double checked the permissions etc. as per a few other who's had problems here). I've have a mac on Sierra - where it doesnt connect either!

I've tried with a new USB cable etc...

And don't know that else to do, now? Any ideas?

I've also tried the fabled double-click for "PC" (win) and "AP" (mac) modes... But, unfortunately, "no cigar"!