Thanks for all the responses. A quick google says I'm not the only one that has encountered this problem. The only tangible advice I read was to do a manual vst scan and look for any failed ones, I did that and there were none. Only one project is a transfer from 8.5, the rest were started in X3. X3 was a fresh install on a new computer, so there are no other Versions of Sonar on it.
My wife has been unemployed for 2 years, so the "buy the next one" won't happen right now. Besides, it's one of those areas that's, umm, kinda weird.

Ye olde "sorry the product you bought from us doesn't work, spend more money" is always a tough sell. I realize that all sorts of variables come into play, but the machine is clean and I don't use a lot of plug-ins. Maybe, somehow the "manual vst scan" produced a miracle, I guess I'll find out.
Wookiee
Does your user profile in windows belong to the Administrator group?
I assume so, I'm the only user/owner of the computer. Isn't that automatic in Windows 10?