I'm so sorry to hear you're running into this! We've had some folks report that issue and tried to resolve it, but we're not quite sure what's causing it in the code. Also, most folks who ran into it were able to resolve the issue by either uninstalling/reinstalling the game or starting a new run until they were able to save. Again, I'm really sorry for the inconvenience and frustration, and thank you for playing despite the issues!