This was a problem for me occasionally in X2 but since I updated to X2a, it's happening every 2nd time I load a project. 

Nothing goes to the master buss. All the outputs of the tracks are correctly set to "Master" and they are all showing output on their meters during playback. But the master buss is silent. No meter activity at all. 

So I shut down Sonar and load the project again. Hey presto, it's fixed. If I restart the project again, the master buss is once again dead. 

VERY annoying!

Havent seen this issue and it wasn't reported to us. Do you have any plugins on the bus? If so its possible that one of them is muting audio to it. Switch the meters on the bus to pre fader and you should be able to see if the bus itself is receiving a signal.

You can also troubleshoot it by creating a new bus and routing all the tracks to it.

Hi Noel, 

Thanks for replying, sorry I seem to have let this post slip through the net. 

I was able to narrow it down an instance of Guitar Rig on the master bus. I always have NI's Solid Bus Comp in there. For some reason, it will sometimes initialize with all of the controls set to zero. Makeup, threshold, dry level, wet level...all zeroed out. 

I have also seen this problem on my reverb bus when I have a Guitar Rig based reverb on there. The project will load with the reverb's wet knob turned all the way down, and the pan knob turned all the way to the left, despite the settings with which I saved the project. 

I think this may be  a Sonar/Guitar Rig compatibility problem because I used the same effects extensively in Pro Tools and never encountered the same issue. 

I suggest logging an issue and mention which version of Guitar rig you are using. Include a test project with the report if possible.

I will do that.