3 ways to permanently erase data on a hard drive

3 ways to permanently erase data on a hard drive
3 ways to permanently erase data on a hard drive

So you decided, for such and such a reason, that no one should be able to read the data that you have stored on one of your hard drives! We will give you several methods to achieve this. When you delete files through the Recycle Bin or reformatting the hard drive, the operating system may remove them from the file list. Normal! However, these procedures do not completely destroy the files in question which remain burned somewhere on the disc. How many criminals have been arrested believing they have erased all traces of their misdeeds from their computers. There are programs and techniques to recover those roughly deleted files in some way. To completely erase data, without any possibility of recovering it, it is necessary to rewrite over it or use special techniques, that is the subject of this article.


Method 1 of 3: The "Boot and Nuke" method

This method will allow you to reuse your hard drive after cleaning. However, even today there is a rumor that despite this method it is possible to recover deleted files. This error stems from an article by Peter Gutmann in the mid-1990s which mentioned this possibility of data recovery. Only, he mentioned this flaw for MFM type floppy disks. With today's hard disks of the EPRML type, the method is flawless. The Lifehacker site describes this software, Darik's Boot and Nuke, as "an open source disk utility (which theoretically runs under all operating systems) for securely erasing data contained on a hard disk., with different methods (Mersenne Twister generator, Gutmann algorithm) The program attacks the computer's RAM and thoroughly cleans the disk.

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Step 1. Download Darik's Boot and Nuke (DBAN) utility here

There are two versions: one for newer PCs and Macs, and another for older Macs. So if your computer is less than 10 years old, you will be able to use this program.

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Step 2. Burn DBAN to CD

DBAN is in the form of an ISO file, you must have a program that can burn this kind of files. In technical terms, we say that we burn an ISO image. It is a special file, since a simple burning of the file is not sufficient. Indeed, on the disc that you are going to burn, there must be a folder entitled "ISOLINUX" without which your disc will not be able to start, and consequently, you will not be able to erase your hard drive.

Windows 7 includes from the start a program that allows you to burn ISO files. All you have to do is double-click on the file. If you are running on older versions of Windows and you don't have a powerful burning program, you can use a program like BurnCDCC

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Step 3. Reboot from CD

Leave your CD inside and restart your computer from this "reboot" CD. If the restart is not done automatically from the CD, you must go to the BIOS configuration menu to select the boot from a CD. On a Mac, you just need to hold down the "C" key while restarting.

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Step 4. Clear the data

You need to select the right drive from which you want to erase data (choose the right drive, because once the process has started, there is no way to recover anything). Set the number of write and erase passes. With three passes, everything will be erased. Note that you can be satisfied with a "single write pass with random data": whatever the method of encoding the information on the magnetic medium, everything will be gone!

Method 2 of 3: Physically destroy your hard drive

This method is infallible, since the material medium is destroyed and therefore its reading is subsequently impossible. Read this article on how to physically destroy a hard drive. This radical solution, if any, is particularly suitable for old hard drives whose data it would be impossible to erase for lack of adequate programs (either they do not exist or you cannot make them. turn). This method is particularly suitable for those who risk having some trouble with the police or the justice! Do we ever know…

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Step 1. Remove the hard drive you want to destroy from the tower or monoblock station

If the drive is external, unplug it from its USB socket.

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Step 2. Undo the top screws

Usually a T-9 Torx key is required. There may be some gaskets, they need to be removed.

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Step 3. Destroy the platters

Once the cover has been removed, you will see a stack of discs (2 or 3) appear, formerly in aluminum or zinc, today in glass and covered with a ferromagnetic substrate: these are trays. Scratch these with a Torx wrench. Then, break them into a thousand pieces with a hammer. Install yourself beforehand on a hard surface (concrete) and rather outdoors. Wear glasses, the pieces fly all over the place. Today's disc platters break easily because they are made of glass. If you have a big hammer or a mallet, it will be unnecessary to open the hard drive. Tap directly on it, the cover and discs will be irreparably destroyed, even if it is an old hard drive with metal platters.

Method 3 of 3: Some Methods to Selectively Erase Files

Even if the utilities that we are going to present to you are not as effective as the "Boot and Nuke" method or physical destruction, the fact remains that they have the advantage of cleaning up the spaces left vacant on your disc without touching what is written on it.

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Step 1. Utilities in Windows

  • Microsoft SDelete: Securely erases files and directories, or cleans up empty spaces.
  • Wipe File: it rewrites the space left vacant by the deleted file.
  • DeleteOnClick: This utility has a "Secure Delete" function based on the US Department of Defense DoD 5220.22-M standard, which consists of rewriting files in a secure manner.
  • Eraser: this is a utility that can be programmed to periodically initiate rewrites of spaces left vacant and track down orphaned files.
  • WBD (Wipe Bad Disk): it is a utility more specially designed to clean hard disks with damaged sectors.

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Step 2. Utilities in Mac OS X

  • Permanent Eraser: to be used instead of the option Empty the Recycle Bin in secure mode. He rewrites the disc 35 times.
  • Disk Utility: this utility is supplied as standard on Mac OS X. It has a Clear free space which can rewrite on the sectors left vacant 1, 7 or even 35 times.
  • srm: this is the command that we use in a console of the application Terminal to erase or overwrite files. The recovery of old data is then impossible.
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Step 3. Utilities in Linux (Ubuntu)

The Wipe application on Ubuntu Unleashed: it securely erases files after successive rewrites, even if it works better on entire folders. This application works a bit like DeleteOnClick on Windows


  • The data can be erased by passing a flame over the platters. It's radical!
  • You can also take out the trays and sand them by hand or with an electric sander. If you work well, you will be able to use it as coasters afterwards! Too kitsch!
  • You can also use a drill with a concrete or metal bit - 6 to 10 holes are enough to render the disc unusable.
  • If you are very into "computers" and if you are a bit of an artist around the edges, you can very well use your hard drive as a Christmas decoration in the tree! A little imagination, what!
  • The more hammer blows you put in, the better!
  • Otherwise, you don't need to unscrew the hard drive, you tap it until the case explodes and you can spray the inner platters.
  • On your next computer (especially if you are considering buying a laptop), consider encrypting your hard drive from the start with software like FreeOTFE or TrueCrypt. You will need to create a password (which will be required when you start your computer) complex enough so that it cannot be guessed and found by potential thieves. So when your computer needs to be replaced, you won't need to physically destroy it.


  • For your safety:

    • Be careful if you use fire to destroy your drive! You risk a fire and the fumes can be toxic!
    • Be careful not to hit your fingers with the hammer!
    • Watch out for flying shards!
    • No hard drives in the microwave! What an idea !
  • In view of the current structure of hard drives mounted on out of the box computers, it is difficult to completely erase a single file. We remind you that the best and safest way to destroy data is through the Boot and Nuke method and / or physical destruction of the disk. Notice to those who do not want to leave traces behind!

    • Once the destruction has been launched according to the advice given to you, know that there is no NO MORE POSSIBILITY to recover any data, especially if you physically destroy your disk.

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