I just upgraded to Big Sur today and my Fireface UFX+ was working fine despite it was running on drivers V321 Firmware 53.
I checked if there were new drivers and found the 327 and Firmware 54.
I didn't check everything but it seems to work just fine with the V321 but just in case I (wrongly) dicided to update.
Now TotalMix doesn't show up and therefore the soundcard doesn't work.
I followed the procedure and ALLOWED the Security&Privacy and when I did the computer just restarted and from there the TotalMix stop to show up after reboot or shutdown.
I deleted all the drivers following the manual page 32 and reinstalled, keeping open the window of Security&Privacy to allow the drivers but there wasn't any RME thing to allow.
At the end of the installation the TotalMix was there and working so I take the chance to update the Firmware to have it uptodate in case it was the problem.
Firmware installation was successful and now the Souncard has the latest firmware.
I restarted the computer and the soundcard is off again and no TotalMix or USB driver was lunched.
At this point I don't know what to do.
My System is an iMac end of 2017 4.2Ghz, 64GB RAM, 500 NVMe internal Drive, Running BigSur 11.6 (installed today).
Until the driver update everything was working as usual, I din't recorded audio but plugins etc were just fine.
Any help will be great as I am a Music Composer and is my everyday tool.
iMac Mid 2017 4.2Ghz 500Gb NVMe 64GB RAM Logic Pro X 10.6.3 Catalina 10.15.7 RME Fireface UFX +