My game crashed while testing my map and I didn't even save after working on it for hours. I kept the window open for awhile hoping it would come back and started looking for the save data. After failing to locate it I open the game hoping I had saved it. In the map maker I did not have any saved maps, but after clicking on the 'manage maps' button I found where the maps are saved. Going there I was still dismayed to see nothing in the maps folder. However I noticed a temp save file in the root directory of the game. I plopped that into the map folder, went back to Lumencarft to refresh the map manager folder & was right back into my map!

It being a temp file, I would guess that if you tried making a fresh map before recovering the map you lost then you might be out of luck. However, the file was up to date from the moment I jumped in to test it (my first wave crashed the game).

• Go here: C:\Users\*Your*User*Folder*\AppData\Roaming\Godot\app_userdata\Lumencraft
  
• Should be a temp.lcmap in the folder
  
• Copy that file to the Maps folder; Load map and make a copy (or several).