I really like all the changes in X3, but I'm having this very annoying problem with SONAR where it refuses to shut down when I quit. The window goes away - yes - but the task still remains in the task manager and I cannot reopen SONAR without restarting my computer. Anyone else have this issue?
 
Other than that - whenever I try to use V-Vocal Sonar crashes. I get that they want us to use Melodyne now but I'm a big fan of V-Vocal and for what I need it works really well.
 

Check to see if BitBridge is also running.  It sounds like you have some 32-bit plugins loaded in a 64-bit X3 install, and these will use BitBridge to allow them to run in the 64-bit Sonar.
 
Sometimes BitBridge will hang, and this seems to make SONAR hang as well.
 
Bob Bone
 

Don't know if it's still a problem. There were a few midi hubs that wouldn't send a necessary command to Sonar on closing. I think they overcame it in X1 or X2 but worth a look under Task Manager processes for midi devices if all else fails.

Could be the driver for your interface not releasing properly.
 
I'd try powering it down rather than reboot your computer.
 
If it doesn't work, you've eliminated one further possibility from your testing regime.