In C7.5, a mixer track when in READ mode, suddenly becomes mute - the mute light comes on,
and there is no sound, even though the wave editor shows the sound to be present.
After a while, say 10 bars, the track becomes live again. If I don’t select READ, the mute does not
come on. If I move the part to another track, the new track does the same. If I delete the part from
the new track, so that nothing is playing on it, it remembers the mute from the original track, and
operates in sympathy, muting at the same point.
Any suggestions, thanks
You need to click ‘show all automation’ and you will no doubt find that there’s some mute automation on the track(s). Sounds like you also have the preference ‘automation follows events’ turned on as well which means that when you move the part then the automation moves with it too. If you wonder how the automtion got there, the I suspect you accidentally clicked the W (write automation) button at some time.
Mike.
Many thanks Mike. That was the problem.
Interestingly, I found a few more mutes littered around the tracks
that I’d failed to notice on account of the sheer volume of too many
tracks playing simultaneously.
Thanks again
Just a final note - if you put ‘Solved’ in the thread title (or ‘Solved - it was automation’) then this will help future people searching for similar problems. Helps to keep the forum tidy 
Mike.