http://imgur.com/GTX6Ghw

LOL that's hilarious! I never even considered upgrading my training levels. Until now. What better way to spend 231,000 caps?

GAH! Upgrading my training levels broke my vault. Each room upgrade makes the room deeper. After upgrading all 7 levels, FOS would no longer load the vault without crashing. Apparently the 3D model became too complex.


Moral of the story: DON'T massively upgrade all your vault chambers. DO make regular backup copies of the VaultX.sav files for rollback. Cloud save would not have rescued me. Fortunately I have three tiers of backup files.