Plt stops working when opening existing projects

Unfortunately, that is not a behavior commonly encountered, and likely indicates you have something going on in your OS somehow.  I remember that I had to be careful to do a Save often with X3e because it might crash, and did crash probably a couple of times during a 4 hour session.  But it never had a startup problem unless there was a VST causing an issue, and in that case it wouldn't open at all until I disabled the VST culprit, and resaved the project.
 
If I were you, I'd open an elevated command prompt, and type "sfc /verifyonly" and when that completes, type "chkdsk c:" without the /F option.  Neither of these will do anything to your computer, but will tell you if you have a system file buggered up, or if you have a file problem on your drive.
 
FYI - Platinum is very stable.  I have to work at it to get it to crash, like insert Pentagon soft-synth and start paging through the presets real fast.

That's quite a workaround Grum. It's not a biggie for me. It's annoying more than anything as I have to restart again but plt is otherwise very stable...just don't understand why restarting fixes it? And it's usually the first time I fire plt up...I usually close plt after each project I work on and I usually don't run into this issue for the remainder of a day's work.
 
Thanks Greg...did your suggested scans without any issues.