I've recently bought the PE Edition to play on the train (playing on mobile Mon-Fri, PC on we). So i copied my existing win10 world to my phone. I played on that, no problems. But when trying to copy the world back on my PC it fails: "Unknown Error". Apparently it's because of the contents of the 'db' folder inside the world folder.
Currently i'm hosting the game on my phone to play it on my PC in VR; works but seems stupid.