If you want to completely erase a hard drive, it’s not as easy as deleting everything on it. To truly erase hard drive data forever, you’ll have to take some extra steps.

A common way to “erase” data is to format the hard drive, but you don’t actually erase the drive of its data when you do this, but instead only erase the location information for the data, making it “lost” to the operating system. Since the OS can’t see the data, the drive looks empty when you look at its contents.

However, all the data is still there and, unless you truly erase the hard drive, can be recovered using special software or hardware. Remember that erase, delete, wipe, and shred are technically different terms.

The most responsible thing you can do before recycling a hard drive, or even disposing of one, is to completely erase the hard drive. If you don’t, you risk exposing sensitive personal data that you previously deleted—data like social security numbers, account numbers, passwords, etc.

According to most governments and standards organizations, there are only three effective methods of erasing a hard drive, the best of which depends on your budget and future plans for the hard drive:

Wipe the Hard Drive Using Free Data Destruction Software

By far, the easiest way to completely erase a hard drive is to use free data destruction software, sometimes called hard drive eraser software or disk wipe software.

  • Free for anyone to download and use.

  • The hard drive is still usable afterward.

  • Must have at least a little knowledge on how to use this type of software.

  • Not the most secure method, since the drive is still usable.

Regardless of what you call it, a data destruction program, such as DBAN, is a piece of software designed to overwrite a hard drive so many times, and in a certain way, as to make the ability to extract information from the drive nearly impossible.

Some more stringent hard drive erasing standards forbid using data destruction software, probably because of the possibility of user error and the variety of software and methods that exist. However, as long as your drive doesn’t contain national security information, you should feel very comfortable using any one of these programs to erase a hard drive.

You must erase a hard drive using this method if you, or someone else, ever plan on using the drive again. The next two methods will make the drive unusable. For example, you should erase a hard drive this way if you’re selling or giving the drive away.

Use a Degausser to Erase the Hard Drive

Another way to permanently erase a hard drive is to use a degausser to disrupt the magnetic domains on the drive—the very way that a hard drive stores data.

  • Really secure since it completely destroys it from being used again.

  • Usually isn’t a free-to-use method.

Some NSA approved automatic degaussers can erase dozens of hard drives in an hour and cost tens of thousands of US dollars. NSA approved degaussing wands, used to manually degauss a hard drive, can be purchased for around $500.

Important

Degaussing a modern hard drive will also erase the drive’s firmware, rendering the drive completely useless. If you want to erase a hard drive, but also want it to work properly after being erased, you must use data destruction software (option 1, above) instead.

Note

For the average computer owner or organization, degaussing probably isn’t a cost-effective way to completely erase a hard drive. In most cases, physically destroying the drive (below) is the best solution if the drive isn’t needed anymore.

Physically Destroy the Hard Drive

Physically destroying a hard drive is the only way to absolutely and forever ensure that the data on it is no longer available. Just as there is no way to extract the written information from a burned piece of paper, there is no way to read the data from a hard drive that is no longer a hard drive.

  • Leaves no way to recover the data.

  • You can do it yourself for free.

  • Could be dangerous without professional help.

According to the NIST Guidelines for Media Sanitization (800-88 Rev. 1), destroying a hard drive makes recovery “infeasible using state of the art laboratory techniques and results in the subsequent inability to use the media for storage of data.” Most of the standards that exist to erase a hard drive mention several ways to physically destroy one, including disintegration, grinding, pulverization, incineration, melting, and shredding.

You can destroy a hard drive yourself by nailing or drilling through it several times, making sure the hard drive platter is being penetrated each time. In fact, any method of destroying the hard drive platter is sufficient, including sanding the platter after being removed or shattering it (as shown here).

If you’d rather not do this yourself, several companies offer the service for a fee. A few services will even fire a round of bullets through your hard drive and send you the video!

Warning

Wear safety goggles and take great caution ​when destroying a hard drive yourself. Never burn a hard drive, put a hard drive in a microwave, or pour acid on a hard drive.

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