Because of a complete system remaking of my Linux server, I had to scan my entire music library on NAS from scratch.
I pointed at the network drive. Initially, I could not see the Music folder. Then, after restarting the NAS (as explained in 1.3 Mac: NAS folder empty [fixed by restarting the NAS]), folder was detected and scan begun.
About half way through the library I had to restart my PC, thinking that Roon Server would resume its scan. However, now the library is back to zero (no music scanned) and it cannot find Music folder on NAS anymore.
I tried to restart NAS with no change.
I tried to stop e restart Roon Server, no change.
Although path to my NAS is enabled (I tried to cancel it and restore it too), Music folder and other folders in that path cannot be detected!
I do not know if it is related to some form of cache.
Incidentally (I do not know if it related), in my RealTime status I see this line:
75 115 /opt/RoonServer/Mono/bin/RoonAppliance --debug --gc=sgen --server RoonAppliance.exe -watchdogport=45663