I had my first vault disappear on me with the latest patch. It had become large and unstable, so I understand why it happened, but I had bought lunchboxes, spent hours shuffling my dwellers between stat rooms to ensure perfect 10's for my wasteland wanderers, and had collected tons of fat men (guns not people), miniguns, rocket launchers, etc. poof, all gone. It was quite vexing as you can imagine and I'm hoping for advice, or just someone to commiserate.