We were playing a mission (2 local players), and when we completed the mission and got to the summary screen with the statistics.  When we advanced the menu to open the chest, the computer crashed.  After rebooting and reloading Dungeons, neither of the profiles are visible in the character selection menu.  The .dat files can be found in the game's character folder (C:\Users\...\Saved Games\Mojang Studios\Dungeons\2590910142773857\Characters).  However, the .dat files do not appear to contain any data.  (e.g. when opening with Notepad, there is nothing but spaces in the file; profiles that are still visible in the character selection menu have data/text within the file when viewed in Notepad).  The crash appears to have resulted in the content of the .dat files being deleted, resulting in the profiles not being using in the game (and therefore not visible in the character selection menu). 

The .dat files for these characters are not in the "CharactersTrashcan" folder.  (Likely because they were not deleted through the game menu, the [corrupted] .dat files are still in the \Characters folder.)

Copies of the .dat files that were corrupted (and characters lost) due to this bug are attached. 

This has also happened to one of us before.  A copy of that corrupted .dat file is also attached.

This has resulted in the loss of items and emeralds (30,000+) that were accumulated through a lot of hours playing this game together.  It is all wiped out because of this bug, as well as our progress through the missions, etc.

This is a hugely significant fault in the game, that characters can be lost if the game crashes at the wrong  time.  This needs to be fixed.  I should not have to manually create a back-up copy of my profile every time I get done playing, just to ensure that my profile will not be trashed if the game/computer crashes at the wrong moment.