I confirm is a good mediaserver solution as UMS.
Only one problem:
systemctl status shadow
● shadow.service - Verify integrity of password and group files
Loaded: loaded (/usr/lib/systemd/system/shadow.service; static; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2018-07-01 10:37:04 CEST; 12min ago
Process: 311 ExecStart=/usr/sbin/pwck -r (code=exited, status=2)
Main PID: 311 (code=exited, status=2)
lug 01 10:37:01 massi-pc systemd[1]: Starting Verify integrity of password and group files...
lug 01 10:37:03 massi-pc pwck[311]: user 'emby': program '/usr/bin/nologin' does not exist
lug 01 10:37:03 massi-pc pwck[311]: pwck: nessuna modifica
lug 01 10:37:04 massi-pc systemd[1]: shadow.service: Main process exited, code=exited, status=2/INVA>
lug 01 10:37:04 massi-pc systemd[1]: shadow.service: Failed with result 'exit-code'.
lug 01 10:37:04 massi-pc systemd[1]: Failed to start Verify integrity of password and group files.
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● shadow.service - Verify integrity of password and group files
Loaded: loaded (/usr/lib/systemd/system/shadow.service; static; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2018-07-01 10:37:04 CEST; 12min ago
Process: 311 ExecStart=/usr/sbin/pwck -r (code=exited, status=2)
Main PID: 311 (code=exited, status=2)
lug 01 10:37:01 massi-pc systemd[1]: Starting Verify integrity of password and group files...
lug 01 10:37:03 massi-pc pwck[311]: user 'emby': program '/usr/bin/nologin' does not exist
lug 01 10:37:03 massi-pc pwck[311]: pwck: nessuna modifica
lug 01 10:37:04 massi-pc systemd[1]: shadow.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
lug 01 10:37:04 massi-pc systemd[1]: shadow.service: Failed with result 'exit-code'.
lug 01 10:37:04 massi-pc systemd[1]: Failed to start Verify integrity of password and group files.