Last Updated May 22, 2011 11:37 PM EDT
Formatting a drive only hides the information from the operating system; it's all still there, and easily recovered in its entirety by anyone who invests even a little time in the process. It doesn't even cost anything to recover formatted hard drives; there are free tools you can download from the Web which will do it easily. And that means if you sell, recycle, or dispose of your old PCs, you should ensure the data on the drives is destroyed, not just formatted.
Don't believe me? Perhaps you trust MIT instead. In a now-famous study, a pair of MIT grad students acquired 158 used hard drives from eBay and other online stores. Of the 129 that actually functioned, 69 had recoverable files and 49 were packed with personal information. They inventoried 3700 credit card numbers, along with medical data and other personal data.
The bottom line is that you should ensure any data on your hard drives are physically overwritten with new data, not just formatted. There are many ways to do this, and many of them are even free.
- CCleaner is a free disk wiping tool that you can use to wipe all the data from your hard drive in a single pass or make multiple passes for Department of Defense-approved security.
- Darik's Boot and Nuke (also known as DBAN) is another free program that can completely wipe the contents of your hard disk by overwriting each sector on the drive.
- Eraser works like the others -- it too is a free disk shredder that overwrites data securely on your old drive.
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