I have a project with a folder containing four guitar tracks.  Three of the tracks won't pan at all and the fourth one, as I pan it (left or right) goes down in volume until there is no sound left at 100%.
 
None of the other tracks have this problem and an older version of the same project works fine.
 
Any notion of what is going on?
 
Thanks,
 
t
 

Toggle Envelope/Offset mode to make sure you're not in Offset mode now (plus signs on pan and volume widgets) or were at some previous time when you changed pan settings. 'O' used to be the default hotkey for this, but it was removed in Platinum because it was too easy to enable inadvertently. There's a button for it in the Mix module.

brundlefly
Toggle Envelope/Offset mode to make sure you're not in Offset mode now (plus signs on pan and volume widgets) or were at some previous time when you changed pan settings. 'O' used to be the default hotkey for this, but it was removed in Platinum because it was too easy to enable inadvertently. There's a button for it in the Mix module.

It is not in or has ever  been in offset mode.  This is not an offset issue.  The meters show the signal properly, it is just that the panning function is not working at all and on one track, the pan knob, moved either left or right, reduces the volume of the track all the way to zero.
 
Thanks,
 
t
 

Any chance you're listening to some combination of individual tracks and a bounced mix on another track, maybe with some phase inversion thrown in? Or are there plugins on buses in this project that aren't in the earlier ones?

Check the interleave button in the track header - make sure they're all set to mono

It was something in the bus.  I had run the guitars to a guitar buss and when they were playing out of it, it was a mono signal, regardless of the interleaf setting.  I ran the four guitars to the Master bus and everything was fine.  I set up a new guitar bus and everything is working as it should.  Although I never figured out what was happening, it is fixed. Thanks for all the input.
 
t