Here is the thing. I had a ship in space that I was using to mine while I built it up, Single player game. I got a touch too close to the planet and got caught in the gravity well. As you can imagine 2 small thrusters in each of the six directions were not enough to rescue three days of grinding and welding and mining. The impact crater was awesome. But all that survived was the control station, 4 drills, several large container's contents of ore, but not the containers, and the ejector port for the stones. I was able to salvage enough to build a small craft cockpit, and 4 large cargo containers. Mostly by building one, filling it, then grinding it down to as close to nothing as I could and repeat the process. I had transferred the contents from the ground and salvaged the drills and other random bits. I started the build of a small reactor as my power was now down to redline. When a probe landed I ran over to it, (About 2 km away), took the refined urainum and ground the reactor for components. I returned to my building site and everything except some of the large chunks of minerals were gone. All the backup games were refreshed but the journey there and back had recycled my backup games past the point where the ship was there. Is this common for half finished player grids to vanish? I was annoyed that the drills full of ore had vanished before but to have everything vanish. This is seriously messed up. 2 years ago I walked away from space engineers because it was so buggy that it became un enjoyable. I can see that in 2 years keen still has not resolved anything.