This is more behavior that I didn't have with Pro, basically what the subject line says. I've noticed that after running Platinum and exiting normally, Sonarplt.exe becomes a zombie process that can't be ended unless I reboot. trying to end process or end process tree in Task Manager has no effect.
 

Win 7 64 pro
Intel Core i7-4770 3.4GHz
24gb ram
Nvidia Geforce GT 635
Onboard Realtek HD Audio (don't laugh, it's surprisingly not terrible!)
USB Audio Interface (USB standard compliant Behringer mixer without specific drivers as per manufacturer)
MIDISport 4x4 Anniversary Edition

The times I've experienced this have ended up being an audio or MIDI interface keeping Sonar from exiting.  If you have a USB rahter than PCI audio interface, you can try unplugging the cable(s) to help narrow it down.
 
1.  Exit Sonar normally
2.  Unplug interface cable and see if the process shuts down

Hi. Does it help if you disconnect your devices? I have this sometimes with my M-Audio Radium 49 (it refuses to release it)...
Best of luck.

Thanks guys, I'll look into that when I get home!
 
It still seems weird to me that Pro didn't have this issue but Platinum does. I thought they're the same code just with more plugins? I'm wondering if I should uninstall everything and try again?

Re-installing is seldom necessary. Try this: Copy the aud.ini file just in case you need to revert to it. Delete the old one and let SONAR build a new one. This is will eliminated references that may not be relevant any more.

I posted advice on the other thread..

http://forum.cakewalk.com...51250&fp=2&p=1

In addition try getting rid of your 32 plugins and see if Sonar safe mode makes a difference.

There is no difference between Professional and Platinum in this case. As I know other DAWs had this trouble as well.
This was discussed million times in this forum, in 2005, 2010, 2015...

I had this problem with my sound card. I use a sound blaster ZXR. when I exited sonar, the card just didnt wanna give it up or something lol. I updated the sound card driver and so far haven't encountered the problem again.

Thanks everyone! As several of you suggested, at this point it looks like ASIO4ALL and/or the Realtek onboard sound that was the culprit. Uninstalling A4A has things working normally, but I can only use my Behringer USB mixer as an out so I'm gonna need to find a nice cheap interface that will output to my powered 5.1 speakers. I'll go start a thread in the Hardware forum for suggestions.
 
Thanks again everyone!