Sellers are currently offering 3807 used hard drives on eBay.com alone. Add 5303 used desktop PCs, 975 Apple Desktops and thousands of other used devices like digital cameras or mobile phones that may contain data that has not been properly deleted by previous owners.
According to Techradar 66% of the used hard drives they investigated were not properly erased, and contained personal data from the previous owner. It's hard to pinpoint the validity of the number because the article fails to mention the number of hard drives and PCs that have been analyzed by the investigative team.
The figure means, if correct, that 66 used hard drives out of 100 contain data stored on it by the previous owner. There is no mentioning what data and how much, but it is likely that some users may not have deleted data at all on the drive, while others may have formatted it at the very least.
But even formatting may not be enough to delete data permanently, especially if quick format is being used for that.
While most studies concentrate on hard drives, any device with storage capacities may also leak data if it is sold on the used market or thrown away carelessly (and picked up by someone else as a consequence).
In the worst case, all data stored on a storage device may still be accessible, from personal photos and videos to financial documents, emails, account information, bank statements, tax information, or business related data that is sensitive in its own right and maybe even confidential.
Imagine someone gaining access to your hard drive in its current state. While some users delete data properly, others do not know about the danger they are getting into or do not care.
How can users protect themselves and their data? The easiest way would be to stop selling (or giving away) used hardware that contained data at one point. That solution is not always practicable though. And even if you do not sell the data, you may still give it away, to a family member, a friend or charity.
The best way to deal with the issue is to use programs that properly overwrite anything on the hard drive so that it cannot be recovered anymore.
If you want to keep Windows on it, you can use the program Eraser for that purpose. Just delete all files as you would normally that you do not want anyone else to access, and make sure they are removed from the recycle bin as well.
Once done, run Eraser and use it to overwrite the free space on the drive so that file recovery software cannot recover the data anymore.
Another possible solution, especially if no data is needed on a drive, is to encrypt it fully, then format it afterwards.
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Ghacks is a technology news blog that was founded in 2005 by Martin Brinkmann. It has since then become one of the most popular tech news sites on the Internet with five authors and regular contributions from freelance writers.