Hi I have to return m my Macbook to Apple, and they asked me to erase the hard drive. I booted from disk went into disk utilities select the Macintosh HD and did a 7 pass erase. But it says in the stats (appear at the bottom) that there is still 6 folders, 425 MB space used and 2 files. Should it not say 0? I am unsure if I have done this correctly. Thanks for any help given.