This is probably the weirdest issue I've seen on these forums. However you SHOULD be able to paste everything in sync in a new project (I don't know the exact procedure but it is supposed to work... I think there is a checkmark or something in the copy/paste dialog that keeps everything lined up). Also maybe you can save a blank template of the original project with just the tracks, settings and effects (no audio) and then paste it into that. Again I don't know how to do that but maybe someone smarter than I can help. But you ARE actually getting signal with everything soloed? Maybe you can export all the tracks and load them into a new project (or a template with all your fx and settings) instead of copy/pasting them. As always I'm just tossing out ideas. I really have no idea what the heck I'm doing. Cheers.

it is extremely frustrating. your ideas are definitely worthy to investigate for sure and, i will ! i have proceed with the project as is and won't fuss with the problem for now. i'll post at a later time on the results of testing your ideas many thanks ! oh yes, i am getting audio playback as you normally would (ie, without soloing tracks) . it's at mixdown where i need to solo all tracks in order to get audio. otherwise its not completely flat lined, there is some audio, but very low and sounds as if coming only from a reverb bus. yes, i tried to isolate the tracks to possibly find the culprit but i can't seem to win.

Right on, man. I just don't want to send you on any more wild goose chases. I hope you get it sorted out. It does indeed sound extremely frustrating. Cheers.