With users having widely reported to be encountering a save glitch in Pokémon X and Pokémon Y’s Lumiose City, Nintendo have now acknowledged the issue and clarified that they’re working quickly to distribute a fix.
Within the statement shared on Nintendo’s website, they clarified that users who save in the surrounding boulevard of Lumiose City (the blue area in the diagram below) risk corrupting their save data.
Hope is at hand, however, even for those that have already been affected. If you wait for the fix, which is promised to be made available in the coming days, then it will not only correct previously corrupted saves, but obviously prevent it from causing any more problems in the future. They’ll let us know as soon as it’s ready to download, so we’ll let you know then!