Hello, First make sure you have an output assigned to the tracks. You will not be able to assign a voice if the track does not have an active output. Also, try reallocating voices to all tracks in the session. -On the first audio track (left most track) hold down Option and set its voice to OFF -All tracks should now be set to OFF -Hold down Option + Command and assign the first track to voice 1. -All tracks after that should be assigned a new voice in sequential order -You may need to manually reassign stereo track voices. Mike