This happens if you try to load a save from a different version of the game (e.g., a pirated save on a Steam copy). Solution: Delete the save, launch the game fresh to create new save data, then replace the new file with the unlocked one.
Help you find the specific mod download. This happens if you try to load a
Incorrectly modified save files can corrupt your game save, leading to loss of progress or even preventing you from playing the game. This happens if you try to load a