Nintendo Japan has issued a warning to Pokémon fans after it was discovered that the latest DS instalment in the series can accidentally erase save data on Game Boy Advance cartridges.
Pokémon: Fushigi no Dungeon Blue was released in Japan on November 17th alongside a GBA version, titled Pokémon: Fushigi no Dungeon Red. If players have both games inserted in their handheld, they can access GBA data in the DS game.
However, if a different GBA game is present in the cartridge slot, there's a risk that any save data stored on it will be deleted. Nintendo has instructed users not to take that risk by leaving the slot empty whilst playing Fushigi no Dungeon Blue, unless the GBA game in question is FnD Red.
Nintendo has also offered to swap copies of FnD blue for new versions which don't erase game data, which are due for release on December 8. And since they've already fixed the problem over there, it's highly unlikely that there will be a problem with the European versions of the game - whenever they might arrive.