I have a Minecraft world that won't show up in the "Singleplayer" saves list. I tried creating a world with the exact same name and replacing all the files in that folder with the files from the broken world, and through that, I've narrowed it down to one file: level.dat_old. I don't know how this level.dat_old can be so important to the game (I'd think level.dat would be more important, and _old wouldn't even be used by the game, a kind of emergency backup).
If I replace everything except that level.dat_old, the save shows up, but when I try to play it, it loads the new world I created, instead of the one I'm trying to rescue.
I've also tried copying the level.dat, and renaming it to level.dat_old, but that results in the save not showing up in the list.
I even tried pulling down the files from a backup I had, but I think they might have already been corrupted.
Is there any way I can fix this? I thought about trying something like an NBT editor, but I'm completely unfamiliar with those, so I don't know how that could possibly help.
Best Answer
A useful tool that I've run into out there is something called Minecraft Region Fixer that may be able to help you solve your issue.
Minecraft Region Fixer is a command line-based tool that scans the files of a Minecraft world save and checks the file structures to see if there are corrupted chunks, or if there are other issues with the world save as well.
In my past experience using this tool, I did notice it was scanning the level.dat files for corruption, and it seemed to have the ability to repair the corrupted file.
If you are not familiar with using a command line, it will be pretty easy if you read the author's documentation on his post. He does a good job of being clear and thorough, and hopefully you will be able to use it to solve your problem!