I’ve occurred this twice when trying to load an older save while in-game during a current save.
I don’t know what caused this but I usually encounter it when trying to load an older save because something unfavorable happened in-game(a character died, or just re-trying a settler joining the village).
Mods in use:
- Anorien biome
- smart crafter
All mods are up to date. Unless they’re not working with current Alpha 17.
Also just got the same problem when trying to quit to main menu from in-game.