My guess is that your card is a class 10 or faster card. Sandisk players have issues with many cards faster than class 4. For best compatibility, use a Sandisk class 4 card. I use only class 4 cards in my Sandisk players, although others report that most(if not all?) class 10 cards will work fine in the Clip Zip or Clip+ when Rockbox is used. Rockbox is a free alternative firmware(operating system) for the player. Rockbox.org. I do use Rockbox, but only use class 4 cards. Rockbox gives many more settings, and much more flexibility to the player.
New micro SDHC(and full size SDHC) cards don’t need to be formatted. They should only be formatted when the card is not working properly.
