Clearing the level cache had no effect I'm afraid. I've emailed the information to the address provided as I've since discovered that any save from the ship works at any time, but any save after the point you reach Fort Joy only works during the session it was created in. Once the game has been loaded, any save from Fort Joy causes a crash.
I will still try the hold-shift-during-boot thing. As for another macOS administrator account, can I access my downloaded Steam stuff from another macOS account or will I need to redownload?
