Disk Scrubber allows you to truly erase removed files from your hard drive when you delete files or folders; the data is not initially removed from the hard disk. Instead, the space on the disk that was occupied by the deleted data is "deallocated." After it is deallocated, the space is available for use when new data is written to the disk. Until the space is overwritten, you can recover the deleted data by using a low-level disk editor or data-recovery software. By using the Disk Scrubber, you can ensure that delete data is written over and thus no longer recoverable by disk recovery software. This is a must when selling or donating your used hard drive.