This time I really think I've got it licked.
No matter what, pre-split your vVocal section then BOUNCE IT TO CLIPS. - Even if it's bounced. do it again.
This will for whatever reason, permit VVocal to create it's region effect without crashing. For like, two weeks now.
 

+1 to this, and I would say do the same with Melodyne too.
 
I've not generally had issues with region effects using the same version of Cakewalk/SONAR, but opening up an older project (i.e. created with an older version of SONAR) with active region effects can be a bit hit and miss.
 
So I try to avoid active region effects as much as possible. If I'm editing anything region-effect based, I do my edits, bounce-to-clips and save. 
 
M.

I haven't used VVocal at all since Melodyne, and I don't remember it crashing on my system. I read about it crashing a lot, though. Thanks for the tip. I kind of liked the way it worked, and I might try it again.

I have the vocal.dll in my vstplugs folder, but it never shows up after a scan (using CWBL). Oh well...  I used to use it.  Alas...

I do this simply because it's the right thing to do. When you slice a section out of a large clip, it still retains the entire clip. All it's doing is hiding the parts you sliced off. Grab an end, slide it out and you'll see the rest of the clip. Bouncing it permanently deletes all of that so the only remaining part is what you sliced out. Now when you slide an end out you'll see nothing.
 
If you're trying to vVocal a large clip it's best to chop it up into smaller sections, bouncing each one. This makes vVocal, or whatever you're using, work much easier on the clip.

Good discovery! I'll try it also. I've found CbB far better than any recent Sonar Plat for handling V-Vocal, significantly fewer crashes. 
 
My template has Ivory piano and Superior Drummer, which are memory hogs. if I'm using 32-bit Splat, I'm pretty much at max RAM usage. I've used 64 bit Splat for about 2 years now, so the RAM should not affect V-Vocal in 64 bit, but yet it does. I have a feeling since V-Vocal i so old that it assumes we're still operating at 32 bit.

 
I've found that my secret recipe is to disconnect or freeze all soft synths first and then use V-Vocal. For years I've always worked with small 1-2 bar clips and immediately bounce after tuning that clip. With CbB I haven't gotten the dreaded crash that doesn't close Splat completely, forcing you to reboot. Fortunately I never get those sorts of crashes any more.
 
When I do get a crash, I quickly double click on the CWP file and I'm back up and running in about 10 sec, since I have an SSD HD. Sometimes I get a blank V-Vocal window, if so I close CbB and double click the CWP file and I'm up and running with no blank window.
 
This method of bouncing the clip before using V-Vocal to me shows that it is some sort of out of memory issue and this also makes me wonder if I can use this new method and not have to disconnect or freeze my soft synths. I'll give it a try.

Selecting a region of a clip and turning on Melodyne for that region already creates a separate audio copy of that region. Bouncing SHOULD be superfluous. That's not to say there isn't a bug hidden in that process that's somehow avoided by creating an extra bounce. I haven't had a problem NOT bouncing, but that only applies to Melodyne, I haven't used V-Vocal in ages and that one did crash on me more often.

BTW, in Splat my vVocal would always load into the Multidock with half the window showing. To get the whole thing visible I had to remove it into it's own window. Was told this is because vVocal wasn't really supported in Splat.
 
It must be supported in CbB because it loads fine into the Multidock there.

@soens: I drag the bottom of the multidock down to expose more. it's faster, clip after clip.
Actually I'm so happy to see it and not the crash dialog. That said, the multidock sucks and is penalizing but that's not a popular notion.

FWIW can someone post a link to some crash dumps for this? I'm pretty sure that the problem is in VVocal which Roland stopped updating 10 years ago. However I can look at it afresh and see if there is something I can do to circumvent.