Was the game created with .13 or did you migrate it from an older version?

Migrated from an older version.
Not sure which I'm afraid (I don't know how to find out), but I bought the game on the 17th May and this is the game I started then.

I have already been playing the game successfully since ...

I was playing the game earlier just fine, then closed it and put my laptop to sleep. After I woke it up, the game opened up fine but when I tried to load my save (and any others) it would crash and say an unexpected error occurred. I restarted the laptop and tried again, but the same thing happened ...