Mac laptop unable to connect to Nucleus due to version mismatch (ref#603PTK)

[Mike_O_Neill]

Check firewall there was a user this week whose Roon Server permission was set off by a Mac update

Sounds similar

Network devices not showing as System Outputs in Roon (ref#41HIJA)

Hello @Richard_Horsley, Thank you for reaching Roon support. Can you please navigate to macOS System Settings > Privacy & Security > Local Network , and make sure Roon is allowed. If it is already enabled, toggle it off and on again. Then reboot your Mac, and see if the same issue persists.