If Roon is seeing your library but not discovering the Bartok at all, we should start by checking the network path between them. The Bartok needs to be on the same local subnet as the Roon Server and Remotes, and discovery can break if anything is separated by VLANs, guest WiFi, or different IP ranges. Please take a look at How do I know my devices are on the same subnet/IP range? and compare the Bartok, MacBook Air, and any router or switch in between.
A few things would help us narrow this down:
Is the Bartok visible in your router’s client list, and does it have a stable wired connection?
Is the MacBook Air running the Roon Server, or is there another Roon Server on the network?
Has anything changed recently in the network setup, like a new router, mesh node, switch, or VLAN setting?
Since you’re running macOS, the behavior you’re seeing may also be 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. Thank you.