Every time I install it in a project, it will work for a minute or two and then all of Sonar freezes. It worked fine when I first got it. Also, it does this funny thing that I've seen before in other crashes where, though I close the crashed Sonar, it is actually still running according to task manager and I cannot re-open it because of this. I can't even end the process in Task Manager, I need to restart my computer to open Sonar again. I've reinstalled both the MS-20 and Sonar to no avail. Any help would be appreciated, thanks.

I get exactly the same thing. It used to work fine in SPLAT but since about 6 updates ago it crashes every time. I've noticed that it will only crash if you have the plugin window open. If you set it up and then leave the window closed (or freeze the track) it seems to be ok. Not ideal but a sort of workaround.

I see this problem or something like it.

When using it I always save the project as soon as the MS-20 has instantiated that fixes it in the project.
Then like you guys if I tweak any settings it crashes SONAR, likewise I have to reboot to clear SONAR.  However because I save the project when I restart SONAR it is there and works fine for the life of the project.

I have reported this to Korg who have in effect shrugged their shoulders and said not our problem, I have also reported it to Cakewalk who have confirmed a little issue with it and said they would confer with Korg.  Not heard anything more back but my work method does not stop me from using it still.

I would urge you both to report it to Korg as well perhaps a few more voices may encourage them to provide a fix, or help Cakewalk provide a fix, if we do not tell them they can not fix it.