Hi Andrew
Try following the instructions I posted in this link which sorted out another member with similar issues connecting to a NAS via Roon
Macs still try to use the flaky AFP Protocol to connect to NAS with Time Machine functionality…and it’s better to use the more robust SMB protocol that Macs use to connect to other Macs
Unmount the NAS using your Finder app…then in Finder, click Go on Menubar…Connect to Server…enter smb://xxx.xxx.xxx.xxx [IP address for your NAS]
Then back to Roon…and now point at your Music folder on your NAS