I can play back this 80+ track tune without having Sonar break a sweat editing this and that abusing the transport.
But:
 
If I dare solo ANYTHING it will play back in that soloed state for about a minute then Drop out.
The only way I can get it to play is to un-solo and then once the track gets going I can solo for about another minute.
 
I must have a derelict machine man.
 
Addendum.
 
I changed the clocking to try to fix another problem in another thread but it did not fix this.
However as a additional bit of interest for perhaps a baker:
 
I soloed the drums and played the track grooving along to them when about a minute in, the bass guitar began to creep in out of nowhere and before I could even think "that's weird.." It dropped out. (The audio engine ceased as it has been).
 
That's inside the Sonar mixer.
 
 
 

This is really starting to get under my fretboard.
 
52 seconds in from start one time, 53 the next. with solo on [drop out]
Seriously? I realize I'm the only one with this issue but not even a wag?
 
Where's that one dude?  :-)

All recorded audio tracks? I wouldn't think solo would have any special bearing, but whenever that many audio tracks are playing and there's a dropout, my first thought is disk I/O buffers. What's the playback buffer set at, and is caching enabled?

Brundle:
 
That Preferences page is as follows.
 
[ ] Read Caching      [ ] Write Caching
 
Playback buffer Size    Record Buffer Size
         256                         256
 
 
NEW 7200 RPM HGST 500GB audio drive freshly defraggler-ed.
 
It doesn't seem to matter what is soloed, regular recorded audio or Thawed VSTIs like Session Drummer.
 
 
 
 
 

I can't repro a problem with a 64-track project, all recorded audio, but my disk is working pretty hard at 256k, and if I were having problems, I would definitely bump it up to 512.
 
I can't think what what else might be going on in your case. Is it dropping out at 52-53 seconds into the project, or does that run-time limit apply no matter where you start playback?

No matter where I start.
 
I've been using Sonar for so long it's not true and I have never seem this weirdo.
I'll up my buffers just for fun.
 
Thanks for playin this round of: "What The DAW!"

I wonder what would happen if you froze a bunch of tracks, and then tried soloing a non-froze track.

I'll try that too- thanks.
 
I have some honey-dos that will come first and the Bronco Win game on Sunday so I may be off the air for a while, that does not mean I don't appreciate you all helping.

Hey bitman, 
 
I hope you work this out and don't jump ship because of a bump,  I see a lot of wanna be "Pro Fools" users out there jump ship on Sonar, just to creep back in here to say sorry.   
 
I know that's not your style bitman, but I just wanted to say that, ...  LOL       

It's cool Jess.