The save data could not be accessed. Please turn the power off and reinsert the Game Card.

[XularusXIII]

Upon trying to start up my copy of Pokémon Black 2, this is the message that I am greeted by. Is there anything that can be done to preserve my data?

[Zorlon]

Just blow into the contacts and try again

Hopefully the save data has not corrupt

all DS consoles have contacts problems with the game cards at some point, specially if the same game has been sat in the console for long periods of time

If you have an original or DS Lite and a GBA + DS flash kit you can backup save data, not sure if a DS side only kit can do this, it may be able to it has been some years since I bothered backing up save data, but doing this from a DS flash kit makes you hot swap carts 2 times (boot flash kit to run backup software, swap carts to retail game you want to backup save from, set software to read save, hot swap back to the flash kit to save the save backup)

Then again if you had a flash you can just play the game from the flash kit that creates a file on a microSD you can copy at any time