First off:
Sonar X2 Studio
Win 7 Home Premium 64bit
 
I am mixing a project and all of a sudden today the Stereo Interleave Button on the Master Bus is stuck on Stereo.  (yes I have rebooted) All other tracks are set to Mono and the interleave buttons work.  I like to switch back and forth from Stereo to Mono as I mix and I cannot figure out if there is some dependency in my project that is forcing the Master Bus to stereo.    I have been reviewing the help and the forums and haven't found anything related to this.  
I save my mixes as new files each day so if I make a mistake or if I want to compare progress I can open old versions.  I have checked previous versions of the project and the last 2 days have this problem.  Older versions of the project do not.  So something I have done in the last two days has created this problem.  I would prefer to not lose 2 days worth of work.  
Does anyone know of anything that would be forcing the master bus to Stereo?

If you can't figure out what you did in the last two days, there's no need to lose any work. There's an easy workaround.
 
Insert Channel Tools in your master bus and set it to mono (L and R sliders at the center). When you want stereo, bypass it. When you want mono, enable it.

bellownc
...the Stereo Interleave Button on the Master Bus is stuck on Stereo...
...Does anyone know of anything that would be forcing the master bus to Stereo?

Maybe a stereo effect applied to the Master bus is preventing it being switched to mono. I think I once saw this happen, but I can't recall which plugin was causing it.
 
One solution would be to add an extra bus routed to the audio device and route the current master bus to it. Maybe name it "Master" and rename the current master to "Pre-Master" or something similar.

Yea, its a stereo effect Kev. Your right. some effects do not let you change the interleave button. I do not know why this is, but i do not think it was like this in the non X versions of sonar (8.5 and earlier)
 
CJ
 

The known bug I'm aware of is (I think it is Direct X only):
http://forum.cakewalk.com/Possible-MonoStereo-bug-for-test-Direct-X-only-m2956642.aspx
 
Check post #4 (as some of this was fixed in X3E, assuming you have it installed, if not you should).
 
Thanks....

Ah you are running X2 sorry, so #1 of that post may (or may not) apply to you...

DirectX isn't even being supported any more by several other DAWs, so don't expect much development to alter this issue.
 
A related issue is if you have a mono track and something like the Tempo Delay in the FX bin. When you try to render something like Melodyne, you won't be allowed to because the mono track is seeing a stereo effect. I just move the effect out of the bin, render, and move it back in again.
 
I really think the Channel Tools solution is the simplest...one click for mono, one click for stereo.

Busses can sometimes become corrupt.
 
The solution is to create a new master buss, re-assign all sends/outputs to the new buss, ctrl/drag any Fx, or save as an Fx Chain/Pro Channel Preset,  then delete the old buss.

Anderton
DirectX isn't even being supported any more by several other DAWs, so don't expect much development to alter this issue.

 
I'm not 100% sure it's DirectX only, but that was the quickest way to reproduce the issue (full details on that thread anyway #4). I wasn't going to point this to other types of plugins because I hadn't fully tested it.
 
As X3E just gave us half a fix for the issue (well I guess you could argue it could be two issues reported as one) I would hope it would end up fully fixed. BTW it "SONAR supports both VST and DirectX effect and instrument plug-ins" so I take that quite literally :)
 
Anyway apols I may be going off topic here...

CakeAlexS
BTW it "SONAR supports both VST and DirectX effect and instrument plug-ins" so I take that quite literally :)

Literally, Sonar does support DirectX plug-ins...apparently too literally, because if the plug-in insists on being stereo, Sonar X2 says "okay."