So I filmed something on a card without formatting it fresh....it had some shots on it from a few days earlier, that I hadn't double backed-up so I figured I would just leave them on the card while I shot some new stuff......I didn't think that would matter.

When I went to dump the card on my Macbook Pro, the card was a bit fussy about mounting...it kept connecting and disconnecting, until it eventually wouldn't recognize it at all. Then I loaded the card back into the camera and it would briefly play the clips, but then eventually said there was no media on the card. And when I tried a regular format, and a secure format, neither worked. It refused to format the card.

I made a support ticket with RED and they suggested formatting it on my computer.

So I'm wondering what's the best way to do that? When I go in Disk Utility, the card shows up, but I don't know if I should be formatting it "OS X Extended (Journaled)" or what?