Pretty much created this account to share this...
I'm constantly being told by friends that their save files are becoming corrupted because they exit Fallout 4 through external means (Quitting the game through dashboard, Power Button, Socket switch, etc.)
I know this goes without saying but:
EXIT THE GAME THROUGH THE PAUSE MENU ONLY!
I tested it for myself and found that the save files do indeed become corrupt, but the scariest thing is, is that it can be any save.
I'm posting this because I know that most Vault Dwellers (myself included) make back-up save files in case anything goes belly up. Furthermore, seeing as how Xbox One has no way of backing up these save files to a USB (anti-cheating measure), we have no way of saving our games from the dreaded corruption.
Good luck and try not lose your saves!