Load Error

Every time I load somewhere outside the Lighthouse, I get a 'Load Error' and can't load the game. It's made the 3rd act basically impossible because unless I finish it all in one go, I can't save and quit. I'm on my second playthrough and it's just come back in that one after being a pain in the butt on my first.

The game will load for a half a second after closing the error message before kicking me back to the main menu.

The game is installed on an internal SSD, so that's not the problem and my graphics are set to medium. Please tell me there's a fix because it's really frustrating.