Going paint balling tomorrow and want to film it with my POV. Problem is, I have just cleared the video footage that was on it. I have checked and it still says it is 7.64gb full, even though it has nothing on it!!
How do I clear it properly.
I am using a Imac.

Thanks all.

did you empty the trash before removing the card, either that or use disc tools to erase the drive/card.

Use a formatting app

http://www.sdcard.org/consumers/formatter/

All sorted, thanks anyway. Used the original VIO to format the disc.

It's 'cos you're using a Mac. Next time it happens, empty the Trash with the card plugged in like mikey-simmo says. Left me confused for AGES when it happened to me.