Oh dear where to start.
I use Sonar Pro and a Focusrite 2i4 audio interface, Windows 10 64 bit.
On a recording I'm working on now, the volume - master mostly, will early on spike to the max and freeze up on playback, and will not stop after I stop playback and start again.  The Master volume meter is just frozen and red max.  If I bring the master volume down all the way to 0 it will stop, but as soon as I raise its level from zero, it spikes again, without even playing back.  The only way to snap it out of it is to close Sonar and come back in and reload the project. But then when I start playback again it will do it all over again.  I have several audio tracks, a couple of guitar tracks with Positive Grid Bias FX plugin, and midi drum, bass, and keyboard tracks converted to audio.
I have no earthly idea what is causing this, but it certainly has wrecked my head and derailed my song project.
I have not had quite this problem with any of my other song projects.
AAaaaaa
Thanks.

Open your project
 
Lower all faders to -INF, now play your project
 
If you're still overloading then uou need to look at the plugins used in the project
 
If it doesn't then you can start bringing up your faders, one at a time SLOWLY, keeping an eye on your meters to see what happens
 

I will try that...my next session will probably be this Friday.
I had brought down the faders that were pegged out (master, focusrite output, lead vocal, and another vocal) to -INF, played it - no pegging out, but as soon as I moved the master, it pegged out immediately.
If its plugins, I'm not sure what to do.
The CPU processing is over 50%...
Thanks - DRP.

What plugins are you using?

I have seen this happen with Pro-channel modules. Particularly the console emulation ones but have also seen it happen with concrete limiter.  Bypass all FX or individual Pro-channels on tracks to see if you can find out which one might be causing this if it is the same thing.

Well it seemed to help when I lowered the master fader down from 100% - at least it didn't happen as often.  Three faders would peg out: master, lead vocal, and an echo vocal.  When I lowered all of them to 0 and played it, the maxing out would go away, and would occur sporadically even with the master at 75%.  Oh well, at least I able to get to a final mix.

Something is causing this to happen to me too.  It was a bass track thru Kontakt 5 plugins were  Autotune, Q10, Rbass, CLA Bass, and Trans-X or Smack. The notes would get stuck on and keep stacking up. Then peg the volume for that track.

Bitbridged 32 bit effects on a bus maybe? I and others have experienced this, and I have learned which plugs to avoid used in this manner.

Sounds to me like you are simply mixing too hot
 
Reduce all faders apart from master by 6dB and try again
 
If it's not enough, do it again
 
Remember, you can always get more volume on your master buss later on in the process