Okay so me and two friends have a world we lan on, and it works fine, we spent hours and hours on it, then later on i was playing alone, and next time i logged on, the world was really slow, when i mined stone and iron, after about 10 sec they'd be replaced, and then when i walked around after about 10 secconds my character would start at the same spot. Then i force updated, still nothing, then retryed countless times but this time half the world was like cut, as if it didnt load, and i could fall down it, but be teleported to the same place after about 10 sec, i tried another world of mine and it worked perfectly, not slow or anything, but that one world is pretty much broken, it was working fine, no mods or anything, didn't mess with it or anything, and it's pretty much gone. Kinda sucks about 50 hours of work gone, anyway is there anyway to fix this?? I really want to keep this world, we don't want tostart a new one because we had to already, i'm running minecraft 1.5.2 and so are they. Tried to do the corrupted world fix, but it didn't work, the one where you copy and paste the level.dat in a new world. but all that did was half the world was gone, fell down and died, respawned in the middle of no where and said my home was missing or obstructed (keep in mind this was the new world which had that world's level.dat, etc.
Youtube.com/DiamondTorchStudios
If u have no luck upload u map to an filehoster and give my the link, i will try to fix the world for u. ;-)