Since you’re running macOS, the behavior you’re seeing is consistent with the newer, stricter Local Network permission controls in the recent macOS releases.
Please try the following steps:
Open macOS System Settings → Privacy & Security → Local Network
Make sure Roon and Roon Server are both enabled
Even if they are already enabled, please toggle them off and back on
Fully quit Roon Server from the macOS menu bar / task bar
Reboot your Mac
After reboot, launch Roon again and check if the devices is avaliable again.
Once these permissions are refreshed and the system restarted, your audio devices should reappear.
Please let us know if the issue persists after these steps, and we’ll continue from there.
Just circling back on this. Were you able to check macOS’s Local Network permissions for both Roon and Roon Server, toggle them off and back on, then fully quit Roon Server and reboot the Mac? Let us know if the audio devices still are not showing up after that.
Yes, indeed, I was able to fully recover Roon on my Mac mini by following the procedure you provided. Thank you very much for your support, and sorry I didn’t get back to you sooner.