The Dreaded Hang on closing issue.

I've read about this issue a zillion times here but it's never happened to me as far as I can remember. 
 
I'm making a CD of my songs I play live so I'm using my backing track projects. I'm just adding a vocal and a guitar track so the band can hear my arrangements of these cover tunes. These are pretty basic with Session drummer, tts-1 ,true pianos and a real bass track. There is also 2 effects sends Sonitus Delay , Lexicon Reverb, and then the LP64 Multi band on the master. 
I've lost track over time and it might be the ones misbehaving are from 8.5. Note I have always used 64 bit Sonar's for these projects. 
I keep opening X3 without thinking about it   Duh,, so I was using X3e. 
All was going fine and I worked my way through all 16 songs adding the 2 parts. I kept working on it over a few days with out issue. I rarely have issues with X3e. 
But last night it was time for mix down and what the heck, I saved the song, exported it, and when I closed it Sonar spins the little circle for 10 seconds and then shows Not Responding? 
Oh well random glitch, moved on and then the same thing happens on the next song? That time I closed using the File menu just to see if I was working to fast. The third song I waited 30 seconds after export , same thing. 
Hmm, Lets try Professional...ahh, 5 songs and no hang up great, then song 6 Sonar is not responding. 
 
I'm off to work and then the band practice tonight so might not get a chance to respond today. 
But If any one remembers any reason Sonar will behave this way please chime in. 
It was not on line. CPU was 20% I put task manager on the second monitor seeing as how I was needing it every 15 minutes anyhow. 
 
 
Oh and Professional was a pain in the end.  It had created an extra buss for Master,Reverb and Delay on each project. 
And all setting for Sonitus Delay have reverted to defaults so everything sounds terrible I had to reset it from scratch. 
So I ended the night back in X3e. 
 
Thanks to all. 
 
Note:  I did use V Vocal on I think 3 of these projects and only on a few short clips. 
 
PS: I love the new Track inspector with  Reverb AND Delay now showing.  

Check to see if BitBridge is running when this happens.  If it is, then one or more of the plugins loaded into the project are 32-bit, and sometimes some of these plugins working through BitBridge can be sporadically problematic.
 
Bob Bone