Had this happening for a while now on and off. When I start plt, if I don't open a project from the start screen and either go to opening an existing project or from file, open, I get the plt 'stops working' message. Restarting the 2nd time usually doesn't have this issue occurring. 
 
I'm curious as to why it doesn't happen the second time?
 
Anyone else has this going on? 

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.

I raised this problem a while ago (Sonar runs ok at the second or third attempt).
I thought I had found a cure - opening Sonar without a project, closing the skylight window in my second monitor and then opening an existing project. The reason I started to do this was that Sonar crashed just when the skylight screen change from the blank project to the existing project.
Unfortunately it crashed the other day using this method so I'm back to square one.

There's two things that bother me with Sonar - the above crashing when loading a project and that it's meant to start up really quickly now. I've seen no evidence of a faster opening through any of the updates that have claimed to be better.

Grum.

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.