Tim, have you tried Cakewalk by Bandlab yet? If your computer receives windows automatic updates, it will become more and more incompatible with Platinum with time.
While Cakewalk by Bandlab is constantly being updated for bugs and compatibility.
It doesn't cost anything to try. I'd suggest you try it and see if you have the same problem with the supported software.
Even if it didn't work, you could get a support ticket to get the issue resolved that way.
I'm a Sonar Platinum guy now using the new Cakewalk and I'm finding it crashes far less and is way more stable.
If you do try it, just make sure you use the email you used when you originally purchased Platinum, so you can get the free crossgrade when it comes out.
You can sign up for free here:
https://www.bandlab.com/sign-upAnd download Cakewalk here:
https://www.bandlab.com/download/assistant/windowsIt requires 64-bit Windows though.