Much to my surprise, upgrading to Catalina knock out my audio i/o units.
The presonus studio192 and the Eleven Rack are not happy …
I've not found any other issues (so far).
But I can't live without professional audio I/O.
I don't use Time Machine, I use Carbon Copy and I have an Image of the
iMac Pro's internal drive … with Mojave, from a couple of days ago.
I just though I would ask, before I start "messing around".
As I type this, I'm downloading an install of Mojave; just incase that's the best way to go.