SDXC Not Compatible With Camera?

I Just Bought an SD Card for my camera and when inserted into my camera (Nikon D40) It says "Card is full" I Have Tried formatting the card in disk utility but that doesn't seem to work. I think my Camera may not be compatible with the SD card as it is an SD-XC and more modern. Is there any way I could make it compatible?

By the way, I use a Macbook Pro, 64GB Sandisk SD-XC Card, And A Nikon D40 Camera.

Nothing you can do to make the SDXC card work in a D40. You need a much smaller card for that camera.

The D40 was made before the invention of SDXC, so it will not work. SDXC came to market in 2009, so basically a D7000 and newer is needed for these cards.

The D40 can use SD or SDHC, but not SDXC. There's not much need for the capacity of an SDXC on a D40. The images are 6MP and there's no video. You should not store your lifetime's worth of photos in the camera. Copy to a computer and then to backup storage media like DVD-R.

Your SDXC card kept in a safe place could be useful as a backup medium for your computer files. If you write files from the computer to your SDXC card, then you should not use that card in a camera. It could be formatted by the camera (a newer one than the D40) allowing it to work in the camera, but that would wipe out any files previously stored on it.

Have you updated the software in your camera? Sorry but you will have to READ the manual to find out how to connect your camera to the computer and upload any up dates for it. I did this when I first got my Pentax Kx and low and behold their WAS an up date to accept the SDXC memory card. I also use Mac computers.