We have another update going live later today which will change the save file format. Unfortunately, this means you'll lose your game progress.
I've structured the save files now so that this shouldn't happen again. It's a byproduct of the game still being in development.
Please do NOT copy your save files somewhere else and copy them back after the update; this will cause game-breaking bugs.
I'm really sorry about this. To help ease the pain, there's a lot of really cool content arriving in 2019, starting as early as January. Don't touch that dial!