Thank you very much for your endorsement, John.

OP here. :)
 
I'm starting to go with the IRQ concept... something interrupting the processing... muddling with the memory. Actual bios level tests of the hard drive and memory come up clean, but that doesn't always mean anything. What I've taken to doing is when I'm planning on working on a file, I do a complete shutdown/restart, and the only thing I'm loading is Sonar. That seems to be helping. It may be that FireFox or Thunderbird is the actual culprit. I actually mixed a song yesterday without a single hitch, with nothing else running. I'm bugger as to why. I guess I need to do some more observation on what's going on in the background to see what I can correlate to this problem. It's got to be -=something=- going on, I just don't know what.  I'm at the stage where I'm mixing songs for locals, mostly for free, sometimes for gear... I've got to eliminate the obstacles... Can't build a local rep as a mixer if I hand out mixes with Squawks in them. For now, clean starts and just Sonar seems to be working.
 
Dave, the files at Indaba aren't bad. You can listen to them in Media Player, or just about any other listening environment, no problem. This corruption is occuring after import into Sonar, and usually long after I've played the tracks several times. As long as I don't save the project after I discover an anomoly, it doesn't write the anomoly into the Audio folder... lesson I've learned, save early, save often, but after verifying track integrity. :) I'm glad to see, by the way, that you found Indaba. For me, it's a great big playground of tracks to practice mixing and editing. I know I'll never win any of their contests (I um... don't dubstep) but there is a small community of serious musicians and it's helped me stretch my skills and work with music I'd never think of producing myself. How cool is this? I'm remixing a new Barry Manilow song!
 
"walla".. Hmmm.. you're right, it is voila. Sorry about that... I think my daughter's texting skills are rubbing off on her dad...

John


This is an odd one. I wonder if the OP might have some device that is cycling in some way. A network adapter or some other time based device that is on the same IRQ. 

The notion of a plugin that is not authorized was a very good idea yet seemingly that has been ruled out. 

I can say this its not normal nor have I come across this in quite this way on this forum. 

One last thing to try is change the audio buffers either via the VST control panel or the built in slider for WDM drivers. 

Also make sure that all the files have the same sample rate. 

Which would probably manifest as DPC latency spikes.  Which can also come from other sources, too (at other IRQ's). 
I think unless you have an older system IRQ issues aren't you're problem. It's resource related or a hardware problem.

BTW - I've used Indaba, and not had problems with stuff from there.  Good site IMO, maybe a little before it's time. Roland should acquire it.  Something like it is where the future is - a DAW offering via software-as-a-service....

OP -  download DPCLAT and check it when this happens.  Chasing IRQ's is frisky business, and dubious too, DPCLAT will tell you something important in terms of solving this problem...

How cool is this? I'm remixing a new Barry Manilow song!

Well.... that's really not that cool... at least not in my book.