I've encountered this before... hit play and there's a loud pop with a specific track/bus meter, maxed-out (constant 0dB) with no sound.
 
The problem is definitely caused by an FX plugin.
 
Anyone knows why?
 
VIDEO: https://youtu.be/slTU9NvZs9c

Yes , I have this problem as well , I have not figured our what plugin is causing it , it usually happens when I add or delete a pluggin while I have sonar playing , restart sonar is the only solution I have found. 
  I was sure it was Slate pluggins for a while but I don't thinks so now.

I've seen that, too. We discussed it in a previous thread. All I've been able to determine is that, in my case, it only happened with a particular project. And although I had traced the problem to a specific track, removing the fx from that track did not prevent the problem from reoccurring. Even now, if I open that particular project I have perhaps an 80% chance it'll play back OK.
 
Here's what I'd recommend trying. Open the project and start playback. Then start removing (not bypassing, deleting) each plugin starting at the busses while watching the meters. At some point the meters may (I use the word "may" advisedly because it's inconsistent) drop to normal values. Make note of the track you were on, then re-open the project and start playback. You may have to do this more than once, because the problem is intermittent. Once you're able to reproduce the problem, remove the fx from that track.
 
This is how I was able to isolate the problem to a specific track. Unfortunately, after placing the exact same plugins back into the track's fx bin, the problem did not re-occur. Not for a few days, anyway.

In my case, it always turned out that the culprit was some plugin that apparently didn't co-operate well with SONAR's 64-bit audio engine.
 
After I finally got tired of troubleshooting seemingly random behaviour and switched the 64-bit engine permanently off, I haven't seen the problem anymore.

Have had this happen many, many times. I think it used to be a problem with the Softtube Saturation module in the PC. 

This problem has been discussed in at least 8 separate threads over the last couple of years:
Plug-ins on Sonar Bus Causing Audio Blowout! (30 May 2017) as bitflipper mentioned
Anyone else experience Cinebells peaking meters and locking sound engine? (20 Mar 2017)
The good old "Loud click / peaking VU meters / DC output / horrible noise" problem... (19 Oct 2016)
really bad noise (29 Jun 2016)
RME Babyface clicks, mutes & peaks VU meters. Any Babyface users seen this? (23 Feb 2016)
Channel Tools POP, then no sound (4 Jan 2016)
Anyone seen this potentially dangerous max output bug? (27 Jun 2015)
Loud Pop from distortion plugin when I save + meter stuck at +9db (2 Apr 2015)
 
It's fairly clear this is not related to a particular plugin. But something is creating denormals as Noel has guessed. You can see this by putting SPAN as the final plugin on the master bus. When the problem occurs, the RMS goes to Inf. Bypassing all FX stops the problem, but it may start again when FX are re-enabled. I've tried stripping a project down as far as possible, but sometimes the problem goes away when this project is re-opened. Again, as Noel guesses, I suspect something is not being initialized properly and is grabbing whatever is in memory. Hence the difficulty reproducing this problem.
 
Cheers, Peter.

KAV
In my case, it always turned out that the culprit was some plugin that apparently didn't co-operate well with SONAR's 64-bit audio engine.
 
After I finally got tired of troubleshooting seemingly random behaviour and switched the 64-bit engine permanently off, I haven't seen the problem anymore.

It's a good thing this doesn't happen frequently else I would probably do the same and disable the 64-bit engine.
 
Thanks for that bit of info.

PeterMc
This problem has been discussed in at least 8 separate threads over the last couple of years

 
This has been going on for years?! Then again, there's a ton of problems in SONAR that's been around for as long as I know so, I can't say I'm surprised. This kinda thing shouldn't be.

Samuel540

KAV
In my case, it always turned out that the culprit was some plugin that apparently didn't co-operate well with SONAR's 64-bit audio engine.
 
After I finally got tired of troubleshooting seemingly random behaviour and switched the 64-bit engine permanently off, I haven't seen the problem anymore.

It's a good thing this doesn't happen frequently else I would probably do the same and disable the 64-bit engine.
 
Thanks for that bit of info.

For me this may explain why I have never seen this happen. My 64-bit DPE has been off since before those threads were posted.

I wonder if anyone has seen this with the DPE unchecked?

I have 64-bit DPE turned off and I get the problem.