World is corrupted

When I go to leave the game, the world gets corrupted and I can never play on it again. This happened 2 time. 1 time (yesterday) I went to go make a copy of the world because I knew my world would corrupt since it happened one time already and mid way through copying the world, it stopped and said I couldnt copy the world because the world was corrupted. I cant even add a picture to show you, it wont let me either... this has been going on for months now and there still hasnt been a fix to this...