Pokémon X & Y update fixes Luminose City save bug
A new patch for Pokémon X & Y has fixed a dreaded game-breaking bug that would cause players to lose their progress while saving in a certain area of Luminose City.
According to some reports, individuals who encountered the bug would find their 3DS systems unresponsive when trying to load the file. Ultimately, they were forced to delete the save and start again.
Update 1.1 for the game should fix that. You'll be prompted to download it when you boot up the game, though you should also be able to download it manually from the eShop.