Does Formatting Totally Erase a Hard Drive?

Zero-fill utilities can remove all traces of personal data from your hard drive.
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When you format your hard drive, it is important to know if the data it contained is recoverable or gone for good. If in fact the formatting process does not totally erase the hard drive data on a PC you sell or give away, your privacy and identity are at risk. With modern hard disks, however, even the low-level formatting utility provided by the manufacturer can't ensure that your formatted drives are clean.

1 Formatting Process

After you have formatted your hard drive, the data it held is still on the device, but not accessible by your applications or your system file manager. This is true even if you do a "full" format. As the formatting utility runs, it writes data on the hard disk that will tell the operating system that all the drive's files are not needed and can be replaced or over-written. Utilities like Wondershare Data Recovery, Bplan Data Recovery and EaseUS Data Recovery Wizard can reconstruct and restore the information needed to make the files on a formatted hard disk visible and usable again. If your operating system writes new data on top of any part of an existing file, however, the original data cannot be fully recovered.

2 Completely Erase a Hard Disk

If, on the other hand, you want to be certain that your hard disk is totally erased and its data completely unrecoverable, you will need to use another set of utilities. Disk wiping applications like Roadkil's Disk Wipe, DBAN and KillDisk will overwrite all the data on a formatted or unformatted hard disk with ones, zeros or random numbers so that it is impossible for any recovery program to retrieve any useful information.

Allen Bethea has written articles on programming, web design,operating systems and computer hardware since 2002. He holds a Bachelor of Science from UNC-Chapel Hill and AAS degrees in office technology, mechanical engineering/drafting and internet technology. Allen has extensive experience with desktop and system software for both Windows and Linux operating systems.