Are you running Sonar as administrator? If not please try it, if you are try not doing it.
Do you have details on #54 ? 
 
Thanks.
 

Holy Smokes Alex!!!
 
That was it. I manually selected to run SPLAT in admin mode and the issue went away!
 
Excellent!</Mr. Burns>
 
I wonder if this will be a SONAR or Toontrack issue?

Yup that error message helped :)
I think you should be contacting Toontrack about this now assuming a clear uninstall and reinstall doesn't clear the issue.
 
Brilliant news...
 
Cheers...

Another thing to do is make sure all your VST's esp toontrack are outside the program files folder where there are special permissions. I've never understood why Sonar defaults under the program files folder...
 
Mine for instance are :
 
D:\plugins\vst\32bit
D:\plugins\vst\64bit
 
Thanks..

I've always made it a practice to run Sonar as an administrator for as long while now.  That might have started with X1.  Maybe the reason, I couldn't repro your problem.
 
EDIT:
Hmmmmm.  The shortcut I use doesn't have "run as administrator" checked.

I've found running as admin can cause other issues so I now avoid.
By moving my plugins as I've described and the odd reg hack (pentagon springs to mind here) it's no longer necessary at least for me.

Modern windows programs shouldn't be dependent on being run in protected locations. Its been illegal for programs to write to the program file folders ever since Vista. If you have current generation plugins that rely on this you should contact their support and ask them to fix it. Some older plugins did do this.

Thanks Noel, What gets me is why their 64-bit plugin exhibits this issue but not the 32-bit. BTW - X3 had to be run in Admin mode too. That is probably why I didn't see it there.
 
I did report an issue and a dump should have been submitted to. The crash was in SONARPLT.

32 bit plugins are hosted by bitbridge so I'm not surprised behaviour is different. Maybe it would be similar within 32 bit Sonar. Either way code may not be identical between 32 bit and 64 bit versions...

Guitarmech111
Thanks Noel, What gets me is why their 64-bit plugin exhibits this issue but not the 32-bit. BTW - X3 had to be run in Admin mode too. That is probably why I didn't see it there.
 
I did report an issue and a dump should have been submitted to. The crash was in SONARPLT.

X64 is more strict about UAC enforcement and the virtualization behavior is also different in a 64 bit app if I remember. It could also be that the 32 bit version of the plugin writes to different locations and doesn't need access to a protected location. If you got a crash send the CWBRN number and I can see where the location is.