Update: I put a disk in my internal optical drive (superdrive) and used the iomega external to see if i could get it to burn a dvd. lo and behold, when i clicked on "close tray," it worked. so it would seem that if i have something in the internal, the external will work. but that is why i bought the external: not all disks are recognized by the internal (i figure it has gone bad). so i was hoping to be able to burn disks with the external and not have to deal with the internal.