Explains How To Avoid It
Pokemon X and Y are thoroughly excellent, as we exhaustively detail in our 8/10 review. However, some players have reported a tragic glitch that effectively destroys their save file, requiring them to start again from scratch. Nintendo are apparently working on a fix, and have told players how to avoid running into problems in the meantime.
The glitch was first reported shortly after launch and confirmed thereafter by many unfortunate players, who found that the game catastrophically crashed upon loading their save file. It appeared to stem from saving in the graphically intensive (by 3DS standards) Lumiose City environment, which Nintendo Of Japan has now confirmed by way of their official site. [via Nintendo Life]
Nintendo are apparently working on a downloadable fix for the problem, and have identified the area in which it can be repeated with a helpful map. Basically: don't save anywhere in the boulevards, and be sure to enter a café or building before saving your game if you happen to be exploring the city. As far as we know the glitch isn't 100% repeatable, but just in case, we'd strongly urge you to follow this advice for the time being.