Minecraft Windows 10 Edition Lost Worlds

This is WRONG.

OP is asking about windows 10 edition which does NOT use AppData\Roaming.minecraft

try 

%localappdata%\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\LocalState\games\com.mojang\

Zaphod77, 

Your response helped  A LOT. I  located the folder with all of my world saves and the data is intact.. I lost a world a night ago when my laptop shut down but I can see it in the folder, do you have any idea how to move the world back into my game so that is playable? THANKS

I just had the same issue - I was playing a world in Minecraft Windows 10 Edition when my game froze and froze my whole computer.  When I restarted the computer and tried to play it again, the world was missing from the list!  I had spent months on this world so I didn't want to lose all that progress.

So, after some trial and error, I got my world back.  First off, open File Explorer and go to:

%localappdata%\Packages\Microsoft.MinecraftUWP_8wekyb3d8bbwe\LocalState\games\com.mojang\minecraftWorlds\

In this directory, you'll see a lot of folders with strange names like "jLUCAlmQAQA=", "0HQAALXzVwA=", etc.  These are your Minecraft worlds.  You can probably tell which folder is for your missing world by the modified date but if not, each folder has a "levelname.txt" file that contains the world name.  When you locate your missing world, there are files called "level.dat" and "level.dat_old".  I renamed "level.dat" to "level.corrupted.dat" (just to keep it around in case this didn't work) and renamed "level.dat_old" to "level.dat".  Restarted Minecraft and voila!  My world is back and playable.

My guess is that at the beginning of each session, the last game state, "level.dat" gets copied to "level.dat_old" in case of corruption so restoring the old "level.dat" file restores the game to the last session before corruption.

Neill, THIS IS SO HELPFUL! Something similar happened to me where my laptop restart mid game. Can you tell me exactly how to to restore the world back into the game? I have the folder with the world in it, but renaming didn't seem to work. After more tampering the rest of my minecraft worlds, the ones that didn't corrupt, disappeared as well but those are insignificant. Any help would be appreciated!

Hi, best thing I can recommend is first to find the folder of your lost world and back it up (i.e., copy it to another safe location like the Desktop or somewhere where you can keep a "good" copy ("good" being relative since the world doesn't work).  At least you'll have a pristine copy in case your experimentation goes wrong.

Now that you've done that, you can try a few different things.  First, I believe the corruption most likely lies in the level.dat and level.dat_old files (perhaps not this last one, but including it just in case).  I just ran a little test where I made a copy of my main world.  Then, I quit and created a brand new world and immediately saved and quit.  I then copied the brand new world "level.dat" and "level.dat_old" files into the copy of my main world and started that game.  It ran and other than the name of the world changing, it seemed to work.  So you might try that.

Maybe my computer just doesn't like me because that didn't work . When I replaced both level files and booted up minecraft, the world that I tampered with disappeared. This is driving me insane, mate! Any more options? Thanks.