UPDATE 2: Problem recreates itself, so I dunno anymore... UPDATE: Turns out me and my friend's player data was mixed up, so the world thought we were the same player (same inventory). When we would get close to each other the world would crash. What I did is download a Universal Minecraft Editor and deleted all the player data. We lost our inventories, but the world is ok and no longer crashing!
UPDATE 2: Problem recreates itself, so I dunno anymore...
UPDATE: Turns out me and my friend's player data was mixed up, so the world thought we were the same player (same inventory). When we would get close to each other the world would crash. What I did is download a Universal Minecraft Editor and deleted all the player data. We lost our inventories, but the world is ok and no longer crashing!