Lost half my file size and about a days worth of building. File size went from 500 MB to 225 MB. When I quit and saved last night the world size was around 500 MB, today when logging in the size is now 225 MB. We lost about 8 hours worth of building. Is this some type of bug? Is there anyway to recover the world?

I make copies of the world every day before loading the world but this isn’t helpful because the copy and main save are at the same point since I made the copy this morning before logging into the world.