Argh… I had high hopes after plugging my UCX into another USB port on another root hub. For two days, it looked like it worked, could not reproduce the behaviour, but experienced it twice when plugging back into the old port. Now today it also happened on the new USB port.
Completely no pattern to indentify, some days it mostly works, other days every project open is a fail 
I am trying to figure out if you are seeing the same kind of issue that I sometimes have. (I am running Cubase 14 Pro with an original RME FireFace UFX connected via FireWire.)
The issue I sometimes experience is that when I open up an existing project it will say “Not Connected” for my audio outputs, and I have to go to the Audio Connections window and re-select the correct device ports for the given audio bus. I have a theory about why this happens, but I’m not sure yet if it’s the same symptoms you’re having.
Are you not even seeing your interface’s device ports unless you reset your interface?
I think I get the that “Not Connected” warning in the status bar when the issue happens, but not for the outputs (not much there anyway), for the inputs. I am not 100% sure this is true and always the case, though. I once thought it was related to the control room, because the sound also comes back when I reload my control room preset, Sometimes I tried reloading my input port preset, and that worked too, but as far as I remember not always. Haven’t paid that much attention though, because I tend to reset the interface in the Studio setup now.
After a couple of days testing with a different USB port, it seems the situation has improved. I still had to reset the driver once or twice after opening a project, but that is way less often than before, when I had to do that several times a day.
haven’t done the test of going back to the old port and using that for a few days…
Via the RME Forum, where another user had this issue (Babyface Pro and Cubase 14: audio issues at 256 sample buffer (Page 1) — FireWire & USB series — RME User Forum) and posted links back to the Cubase forum I found another thread where people had similar issues like ours:
(Didn’t see that in my searches, because of wrong search terms…)
In this thread, a Steinberg rep actually got involved, in the end also assuming it might be a timing issue:
there is another thread in which someone had solve the problem by doing a reset of Totalmix:
This didn’t work for me. What worked was actually using a different USB port. I tried two other ports where I couldn’t either reproduce the behaviour or the occurrence was extremely rare. Going back to the old port immediately immediately let the issue return.