How can I format a Sandisk 64 GB memerory card for my EOS1D Mark2N?

[cicopo]

I don't think you can. I think it only recognizes up to 32 Gigs but just in case I'm wrong use The Canon Downloads & Support site to verify that by checking the firmware update notes.

[holt]

Thank you sir.

[ebiggs1]

Also check the speed. It may not be able to take advantage of vey fast CF cards. And, I am going to guess a 64 GB is a pretty fast card.