XBox 360, refurbished first gen

Un-patched game

Sorry if this is the wrong thread but I'm dealing with a specific problem, not just commenting on the game.

The game plays okay for the most part but eventually will no longer load. It starts the loading screen (blah chunks blah) and freezes. I've lost 8 worlds this way. I have found there is a glitch about the save/exit option and stopped using that, using only save/do not exit. Despite this the world will (eventually) no longer load or will freeze almost immediately.

My questions: is this a known problem? Is there a patch for it? Have any of you had this problem? Any solutions?

Many thanks, friends.