Doing some editing for some music for my wedding and had everything sound great a few nights ago, then I opened it up today and the ProChannel decided it didn't work on one track any more. Nothing worked. Re-started Sonar. No avail. I think a few people have been seeing this one. Did some-one determine what the problem was? Is it related to using BitBridge? I did have a few 32 bit plugs on it..

What plug-ins are you using on the track that doesn't work? If none of them work, start it in Safe Mode and eliminate plug-ins until you find the culprit. Its probably an old effect or a freebie that doesn't work. 

I am thinking along the lines of Dave also. Yes, Sonar is finicky with crappy plugins. Sometimes they work just fine when you start and work on a project. The scenario leads you to believe that all is well...until, however, you save, close and return to work on the same project another day! Then it's, "On your marks, get set...CRASH!"

Probably got nothing to do with it but freezing a track diables Pro Channel.
 
Just a furry thought.
 
 

Hmm, I'll have to play with it some more. The plug I had was Camel Crusher. Maybe that was the issue.. But I THINK I've had it also happen with only Concrete Limiter in action - though it was a while ago and I can't remember if I used anything else... I wish all my plugs were 64bit :(

Maybe J Bridge instead of BitBridge might help?

http://www.camelaudio.com/camelcrusher.php

Oh, and no, not freezing it! :p but it is greyed out as though I did freeze it, kinda. Well, half frozen. Not everything is grey.

I would avoid using a bridge at all by installing the 64bit version of CamelCrusher.

Probably not the case for you, but if you have Melodyne or something that transfers audio on a track, you will have to click Post on the track or else ProChannel will be bypassed.  In this case, PC looks like it is turned on, but it doesn't do anything.
 
If this isn't your problem, maybe this will help someone else.

Oh, didn't realize. It probably is the 64bit version I have then! I would have installed that given the option. Will check.