I can't seem to burn DVDs from iPhoto using my Mac Pro. Everytime I put in a blank disk, either iPhoto doesn't recognize it as being a blank (and spits it out, asking for a new blank disk) or it accepts the disk but tells me it is full when I try to write to it from iPhoto. My hardware is all stock with the Pioneer OEM burner in my Mac Pro. I have tried multiple brands of disks (Maxell, Imation) to no avail. Also, all of my apps are up to date (OS X 10.8, iPhoto 6.0.5). I can burn disks just fine outside of iPhoto, and I can even drag and drop iPhoto images into Finder and burn them that way. Any ideas on why this would happen with just iPhoto?