Maybe I'm just pushing Sonar a little too far but I've gotten the audio engine stop messages while chasing the now time meter cropping clips. Essentially I'm just removing the beginnings of clips up to the point I want to use while Sonar is playing. Doesn't happen every time and it doesn't crash anything. Just wondering if this is an indicator of a deeper problem I should be looking at. Cheers.

It is most likely due to the audio engine not being able to keep up. Sonar was/is not known for a gapless audio engine. You could try upping your audio buffer.

When I do editing I stop the transport. 

That is an excellent point, John. I've got my buffer/latency settings set to the lowest values. I forgot about the whole "bump it up a notch when editing" premise. Ha... it's a good sign for my system that it actually DIDN'T crash while I was doing that. In fact now that you reminded me about that I'm surprised I was able to do what I was doing at all. lol... Thanks, man. Hope you're having a good weekend.

While at this topic, may I add to the question, there is a windows pop-up saying the audio engine is stopped, click to continue. And there is an option not to show the message again. 

I'm now getting better at avoiding this (tweaking the buffer depending on recording or mixing, and to freeze track when done) Anyone know where to turn this message display on again ?