I just had this happen too. Going to revert to a previous save and hopefully will fix. Only commenting because I'm running a special PC that I purchased optimized for Factorio (I know right?), but the guy that set it up overclocked the ram and I think that is creating errors. I have seen specific wa...

Hello, Steam says I have almost 16,000 hours of play time, haha. My biggest world runs 24/7 when I'm not doing something else on Steam, and can go weeks without intervention, but the FPS/UPS is only about 7.0. And so I've taken all my incredible (for me) blueprints and started a new world with 60/60...