The error message appears when a game save was corrupted due to the game crashing or closing during a save. There is currently no way to fix it.. I am sorry it happened, and I will do my best to make it more resilient to that in the next patch.
Cool. Is there a way to delete the save so I don't have to see it anymore, or am I just stuck with it until I'm able to do so?
Go to this location on (usually) your C drive (copy and paste works in the file location of your file browser)
%appdata%\..\LocalLow\RalivDev\Archipelagates\saves
You can then delete the save file directly and safely from there.
You can make backups by copying the file if you want, too.
