Well that's pretty cool. At least there's a possible workaround. Thanks.

I have the same problem.  In the heat of a session doing multiple takes it can be very frustrating- as Sonar crashes pretty consistently under these circumstances.  Many times I have to reboot.  (I'm using the V-700). So it's save after every take- which should be normal- but with all the other stuff going on one can forget.  I seemed to experience this more after the X1D patch.   

What sort of crash are you talking about? Whatever the type, you should NOT be crashing regularly with your system.

my crashes today:
2x UAD insert on channel
3x Maschine insert (this one is the most)
1x Regular Playback while adjusting reverb VST


strangely, i seem to remember Sonar popping up some kind of reporting window to send to Cakewalk and now it no longer does?

"What sort of crash are you talking about? Whatever the type, you should NOT be crashing regularly with your system."

Well Amen that it SHOULDN'T be crashing a lot but it IS.  Pretty much just as the OP describes.  Sometimes Sonarpdr.exe stays open in the background and the only thing I can do is reboot.  Sometimes closing the VS700 does the gig but lots of times it's reboot.  It happened this morning in a session with two clients here!  It's not the end of the world for me as I'm aware that I HAVE to save after every take.  It's just a bit frustrating.  8.5.3 seemed to be pretty stable compared to this.  Again, I aint exactly ****ing but...

I have the same problem, especially when I use v-vocal. Like you, I can not shut down the process. Things seem to go to pot if there is a crash when I have a midi keyboard connected. My "fix" is loging off of windows (not shutting down, just a quick logoff/login. When I do that, the process is gone and sonar can be started and run normally. By the way, since I gave up on v-vocal because of instabilities (in Sonar x1 64 bit only, not 32), and went to Melodyne (which is GREAT, 10 times better than v-vocal), ALL that instability is gone because I no longer use V-vocal. But the log off/logon trick is what I did before that and saved a lot of time over rebooting.

My X1 crashes when trying to use Rapture, and I have documented that in some depth elsewhere. When X1 crashes, I too need to re-boot, before I can start X1 again, and the .exe program is still running, and visible in the processes tab of task manager.

The only device connected to my workstation when this happens is my Roland QUAD-CAPTURE.

I have raised a support ticket and I am still awaiting a response.

I was having problem with a bad install of the N.I Kontact retro machines 2.
I had too click end process on the SONARPDR.exe about 4 or 5 times to end.

Eventually sorted by downloading again using a download manager and re-installing the sound set.
JD 

@synkrotron... I know it's long distance for you but if it's causing a serious disruption in your work it's easier to get a response from Cake support over the phone. Both times I've called I was only on hold for a few minutes and it was well worth the wait and few bucks of LD charges. Extremely helpful folk. Cheers.

Oh and keep an eye out for new QC driver updates. I think a few people have been having issues so I'd imagine Roland will be attempting to release new drivers. At least one would think so anyway.