JohnEgan
Still on Win7 on my DAW PC though, maybe Ill finally switch it to Win10 despite not liking interface, or change in general.

I stayed on Windows 7 for as long as I could. After upgrading to Windows 10 I wish I had done it sooner.

I stayed on Windows 7 for as long as I could. After upgrading to Windows 10 I wish I had done it sooner.


 
Its those annoying Win10 reminders that may break me (albeit more so your advice), guess its time to bite the bullet.
Cheers 

Vocal-sync IMO only works on flat tracks, tracks that haven't been melodyned or audio-snapped, or probably on clips that have a plugin stuck in the clip.  If you have those, you gotta bounce them first (methinks) so they are just a wave file sitting in a clip.  Whether I am right or wrong, I've had no problem vocalsync-ing .... other than after vocal-syncing applying some minor trimming and/or fade-out as may be required to make a flawless match.
 
I don't have any problems under Windows 7, and plan on staying with that past 2020.  If you have Windows 8, I agree with folks above you should probably go to W10, but be advised that you are going to have to tweak a bunch of stuff to turn crap off that uses cpu.  The only thing that should be using your cpu should be Sonar, and that is probably why I don't have problems (other than stupid stuff like get blackout drunk and become Super Mixing Engineer, ta da, and destroy a whole sesson).  There is probably a How-to somewhere on this forum.  How to set up Win10, not get blackout drunk.  PM me if you need those instructions.

I really didn't tweak anything after switching from 7 to 10 and find the whole thing very stable.

Well, after switching to Win 10 the crashing has pretty much stopped.
It still does once in a while when I shut down certain projects.
 
Suddenly Vocalsync works, but as MacFurse said I just make sure to "bounce to clip" after I use it.
Are there any alternatives to Vocalsync?
 
Oh, and I did reinstall SONAR and Melodyne.
Command Center doesn't make clear where Vocalsync is but I assume it reinstalled with SONAR.
 
Also, if anyone has those Win10 tweaks I would appreciate a link/list.
 
THANK YOU everyone for your great advice and help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Vocalsync is part of the core app I think. There's no alternative in Sonar that works as easily, but obviously you can use Melodyne or AudioSnap to manually line up vocals