Save keeps getting overwritten on every startup

Basically, every time I start up the game, my save file gets overwritten with a fresh file, meaning I have to adjust my button settings, as well as unlock characters and colors, every single time I want to play this. I’ve tried:

Running game as administrator
Running Steam as administrator
Uninstalling and reinstalling the game
Uninstalling and reinstalling Steam
Running the game outside of Steam
Downloading a save file off the internet
Installing Steam to a different HDD
Sacrificing a lamb to the dark lords

Any idea what’s causing this, and perhaps how to fix it?

Edit: It’s doing this on both of my computers