When I think of it, I bet I get that message on a project that I hit Shift A by mistake instead of Ctrl A. Shift A opens Audio snap, and I close it right away, but this makes sense.
Thanks for solving my mystery too! So your right, it's embedded somewhere, I wonder if clearing that "Aud in" or the "picture cache"  would help?  I'll try it next time I get the message. 
I have never performed either of those operations but it seems a common suggestion. 
 

I was going to suggest it was an inadvertent keyboard shortcut invocation of audiosnap. The easiest way to clean audiosnap out of a project is to save the project as a bundle. Also may want to re-map the keyboard shortcut if it happens too often.

I’ve run relatively high track counts with multiple plug-ins inserted in the effects bin and transient markers displayed on every track without any issues.
 
I am guessing so I may very well be wrong but, if you haven’t moved any of the transients on a particular track, it doesn’t process that track during playback.
 
Also, there are two modes of processing, (1) an on the fly process and an (2) off-line line process.  The on the fly process is supposed to be easy on the CPU and shouldn’t consume massive amount of processing power but, you may hear some anomalies that will go away in the final mix-down.  The off-line process is CPU intensive and happens during mix down.
 
My suggestion is to move the transients around to your heart’s content on your track of interest and then mix just that track down by itself (bounce to track or export).  Save your project with a different file name and delete the original track (to avoid confusion) ... and see what happens.
 
Out of curiosity are you running 32 or 64 bit (I am assuming 64 bit based on the 12 gig of RAM).

Cactus: I've remapped the Shift-A to something else, so I have to enable Audiosnap on purpose by clicking the icon. But it seems non-intuitive to me that when I select only one track, it starts creating transients for everything, anyway. Then, if I select ALL the tracks and disable AS (by turning off the little icons inside the AS box), the transients seem to go away, but apparently they're still there. 

Dave: yep, it's 64 bit. And I do as you suggest, that is, I move the transients around on a single track, then bounce to clip (or track), and it re-renders it and clears the transients. But there are still transients on all the other tracks. I'm just wanting it to work ONLY on the tracks I've selected, the way similar "elastic audio" plugins do in other DAWs. So, to stop it I have to bounce ALL the tracks (or create a bundle), which seems excessive (why can't I just turn it off?) The point of this thread was that I thought I was missing something basic, but I guess not. Thanks for the tips... 
 
--j

Highlight all the tracks you want to disable, Click on Views, Audio snap pallete, then in the audio snap panel click the Power button (next to where it says audio snap) That will enable or disable audio snap on the selected clips. Hope that helps!

Caa2
It doesn't.

Thank you.

It most certainly does. I do it all the time and verified it it Sonar X1 as well as Platinum before I posted. Here's the thing, once you've disable audio snap, IF you click the audio trainsient tab under the track name (clips, audio transients, automation, clip automation) you will Re-enable it. The trick is not to click that tab again or you'll turn it back on. And it will stay on until you disable the way I described or bounce it. Trust me though, Audio snap is my JAM! 😄 Perhaps you could describe what symptoms you are having or why you don't think it's off.

Good Day,
 
I haven't read through all these posts fully, but I recently had an issue with audio snap remaining enabled in the inspector window under clip/audiosnap, after having enabled audio transients in track to quickly look at the approximate tempo of a random recording, and then returned to clip view, I noticed it because later I couldn't invoke Melodyne on a clip, and found audio snap enabled in inspector/clip/audiosnap was preventing Melodyne FX region being available, not sure this is same issue but I dont believe Ive ever had to do this before until recently. Anyway not sure this is any help, but an experience I had recently.  
 
Cheers