2 Replies Latest reply: Feb 28, 2010 9:04 AM by BobHarris
Tigeraptor Level 1 Level 1 (0 points)
in the disk utility, there is an option to erase free disk space.
what exactly does this do?

MacBook Pro, Mac OS X (10.6.2)
  • CT Level 6 Level 6 (17,010 points)
    From Disk Utility Help:

    "When you delete files by emptying the Trash, Mac OS X deletes the information used to access the files but doesn’t actually delete the files. Although the disk space used by deleted files is marked as free space, deleted files remain intact until new data is written over them. As a result, deleted files can be recovered.

    You can use Disk Utility to erase the free space used by deleted files by having zeros written over the space once, 7 times, or 35 times. If you have a lot of free space on your disk, overwriting the free space several times can take a long time.

    Erasing free disk space does not erase the other files on your disk."

    charlie
  • BobHarris Level 6 Level 6 (15,580 points)
    in the disk utility, there is an option to erase free disk space.
    what exactly does this do?

    It creates a file and starts writing zeros to the file, growing it bigger and bigger until it uses up all the free space on your disk. Then it deletes the file and all the free space is now zeroed.