Whats the difference of these two?
I cannot play anything on an external instrument thats input is on a track that’s either muted or off… there seems to be no difference?
I don’t know the exact idea behind this, probably this is meant for live use and CPU-Saving.
But the difference : When you mute a track the audio in the track just gets muted, the effects stay on (a reverb will still reverb), when you “unmute” it the audio continues immidiately, whereas with “off” you completely cut a channel off, means the effect chain is cut too and if you set it on again there is no sound until a note/sample is triggered. This is important if you use long samples etc.
edit:well, actually it is a bit different (and makes no sense to me). If you “off” the channel gets cut and the effects play on, if you mute the audio is set to inf. dB but the effects get cut. Strange. Shouldn’t this be different ?!
“Off” only avoids that new notes get triggered by the patterns in the track and stops the playing note(s). This is usually what you want, as you can still play notes via the keyboard in that track, and the CPU will go down as soon as the notes stopped playing.
“Mute” is a classic mixer mute, setting the volume of the track to 0dB, so you cut/stop the track at once. The track continues playing, but is simply not audible…
Hi… Thnx for the clarification 
I thought it should work like that… This also explains my confusion → “Input device” stop working on channels if track is put to off state.
Forgot to say this in the earlier posts… perhaps this needs a fix because now it does not work as supposed if you have a “line input device” on the channel that’s switched off. all the other plug-ins work but the “in device” doesn’t… so sample playback on such channels work normally but the external synths cannot be played.
Perhaps I just found a bug then…in the newest couple of versions, Renoise will pass the audio on to any send device in the DSP chain, even if the track is muted. This is definitely not how thing used to work, and very annoying IMO…