Using NoMachine 9.6.3 on both server and client. Windows 10 client. Server is Ubuntu 26.04 LTS.
The “Mute audio on the server” box is checked in Audio settings in the client NoMachine instance, but sound is still heard from the server (as well as on the client). The server’s speakers are attached via HDMI (integrated with the monitor), but this may no longer be relevant in Ubuntu 26.04 because Pipewire is now the default server and provides an abstract “Mute the default output” operation.
pactl set-sink-mute @DEFAULT_SINK@ 1
successfully muted my server speakers while stil allowing forwarded audio to play on the client.
pactl set-sink-mute @DEFAULT_SINK@ 0 un-muted.
-Jim
P.S. Similar to Issue 52047 (which is locked and supposedly fixed in !nm v9). I had already switched to Ubuntu 26.04 before !NM 9.x landed