Yeah that's a painful error that only seemed to pop up for me in v4.4 AND v4.5. The game has been updated twice and is now v4.7. I would strongly update first. My saves are also from v4.4 and I took them with and I almost never have that crash anymore unless there are massive characters or growth. In v4.4 and v4.5 having a single save only helped prevent that error for some reason but I currently have 3 saves.