I have a Macbook with an upgraded, but previously used hard drive.
I know that Macs have an option to 'securely delete' files, which essentially copies over all the file data with random 0's and 1's.
If possible, I would like to do this with all the unused space on my hard drive to clean it up. I think this is similar to what defragmenting does, correct?
Anyway, how can this be accomplished? Is there a way to do so with Disk Utility perhaps? Any help is appreciated!