I'm making a PvP arena plugin, and there are several ways the players can modify the map they play on. Obviously, I don't want the changes to stay there (and the changes are too numerous to keep track of and revert one at a time), so I want to unload the world, delete the world folder, copy the backup, and load the world. During the restoration, players are in the "lobby" world instead of the main one. Code: plugin.getServer().unloadWorld("world", false); /* Code that deletes "world", copies "world_backup" in its place. I've verified that this code works separately. */ plugin.getServer().createWorld(new WorldCreator("world")); When this part of the code runs, the server complains like crazy that an external source is accessing the map and then it crashes. Am I not unloading the map fully? Is there a better way to accomplish this?