Storyline automatically closes after in-slide preview

Thanks for the reply, Leslie. 

I am working in v3.56.26145.0.

And, yes, I understand how the auto-recovery feature works and am grateful for it in most instances. Unfortunately, since the spacebar prompt issue is different (i.e. not the result of an unexpected crash or file shutting down) - since I clicked "ok" without recognizing what the message was asking, it doesn't really apply here.

I did try to find the file in my temp files folder but alas keep getting the "This process is locked/You don't have access to this" message. (I'm paraphrasing the message, but I'm sure you recognize the one.) 

I have rebuilt my file with the lost work and of course, the material is proprietary and highly regulated so I'm not able to share it. If this happens again, I'll save my file and sanitize the proprietary info so your support team can have a look.

Thanks again for the reply.