How To Protect Sensitive Information by Erasing Your Hard Disk Completely

Varun Kashyap 20-07-2009

How To Protect Sensitive Information by Erasing Your Hard Disk Completely harddiskMaybe you are giving away your computer to one of your friends/family, or perhaps you are lending your hard disk to a friend. You don’t want them to be able to get your data and see what you had stored on your hard disk, so you delete everything and scrupulously make sure that you cannot see any file and folder within Windows Explorer. Feeling satisfied, you lend it away only to realize later that files can be retrieved even after you have deleted them from the hard disk.


So what should you do to ensure that the files were “really gone” and could never be retrieved. For starters, never say never! As long as you don’t dismantle and physically destroy the hard disk, your files can be retrieved (and you thought recovering files after an OS install was impossible). That being said, chances are you won’t have to worry about forensic experts trying to get super secret formula X from your computer.

With a little care, you can be pretty sure you would be able to dodge the attempts of your overly geeky friend. Here’s how.

Format, don’t just “quick format”

First off, when the operating system is running, you cannot be sure if any files are actually deleted. At the very least, you have to format your hard drive. So when you decide to do so, don’t save time by doing a “Quick Format” – it doesn’t delete files, use the other option and perform a complete format which will erase your hard disk completely.

You can achieve this by booting from Windows disc and choosing the appropriate option. Linux users can boot from one of the live CDs and use the fdisk utility to format the hard disk

How To Protect Sensitive Information by Erasing Your Hard Disk Completely format


This should take care of any fears of data recovery by novice users

Securely delete the files

You can step it up a notch by securely deleting files from the hard disk. A secure delete not only deletes the files, but writes random data onto your hard disk as well, making it extremely (I mean EXTREMELY) difficult to get the files back.

If you are erasing your hard disk completely, you can use Darik’s Boot and Nuke, securely deleting data is the sole purpose of existence of this bad boy. Boot DBAN and let it do what it does best.

How To Protect Sensitive Information by Erasing Your Hard Disk Completely dban


How To Protect Sensitive Information by Erasing Your Hard Disk Completely dban1

If on the other hand you want to securely delete files from a USB stick or external hard drive you can try previously mentioned How To securely Retrieve and Delete PC files Read More and very useful Eraser. It integrates with Windows shell and lets you perform secure deletes from the context menu.

These methods would pretty much have you covered, but be warned: an adept professional may still be able to retrieve files although these methods would still give him a pretty tough time.

Do you know of better software or tips that you use for similar purposes? Mention them in the comments and share with the world!


Related topics: Hard Drive, Online Privacy.

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  1. Dean
    August 13, 2009 at 9:49 am

    I just have a question for you guys, waiting for an answer with a big signifiance for me.So, if you have in your computer a file(word,jpeg,txt,xcel...any kind of file)and you transfer this file in other computer(using a memory stick,cd,e-mail,etc)there is something in that file as a specific information about your computer(the source),something as an ID of the source computer or...let's say something about the serial number of your OS?Something which can identify exactly the source computer?Something as a fingerprint?I was asking myself which is the answer and I was asking others,also.No answer, up to this point!Thank you anticipate for your support!

  2. Ddx30
    July 23, 2009 at 7:06 am

    I did try Eraser, but recuva will always find back the files eraser was supposed to delete, also when cleaning empty space in the disk... many times. I found out that Wipedisk and wipefile both do much better clearing content form the HDD, beyond recuva in normal mode (never had patience to go in deep scan :-)
    I am not related in any way or form with the wipedisk and wipefile creators, distributors colaborators, coders or whatever, I just use them.

  3. Prajesh
    July 21, 2009 at 11:27 am

    revo uninstaller has the feature of unrecoverable delete. but this deletes only the previously deleted or formatted data on your hard drive.

  4. Dave P
    July 20, 2009 at 4:09 pm

    Eraser does it all. It can create a nuke disk for full drive wiping. In addition to integrating with the context menu, it can also integrate with the Recycle Bin to securely erase files in there. Lastly it can overwrite unused space on a drive to wipe out tracks left by temporary files and others which don't go through the recycle bin.

  5. Sergio
    July 20, 2009 at 2:07 pm

    or you know, stick your harddrive in the microwave for 1:00 minute.

    Or sweep a big magnet back and forth many times will do the trick.

  6. Neo
    July 20, 2009 at 10:48 am

    Nice tips... but how about writing on how to retrieve them? ;)

  7. Martin
    July 20, 2009 at 10:26 am

    For Linux users (Ubuntu is my flavour) you can use Shred and/or Wipe which will do the same as mentioned in this article. Shred comes by default in the latest versions of Ubuntu but Wipe will have to be installed. Open a terminal window and type

    sudo apt-get install wipe

    Then, for greater convenience, you can add Shred and Wipe to your right-click options. To do that you'll need to install Nautilus Actions, so again open a terminal window and this time type

    sudo apt-get install nautilus-actions

    Once installed just follow these instructions
    : Go to System > Preferences > Nautilus Actions Configuration

    : Click Add and use these settings
    : Label= Shred This File
    : Tooltip= shred utility to securely erase files
    : Icon= gtk-dialog-warning
    : click "Add" button
    : Path= shred
    : Parameters= -f -u -v -z %M

    : Click Add and use these settings
    : Label= Wipe This ENTIRE Folder
    : Tooltip= "Wipes" the ENTIRE contents of the folder and then the folder itself
    : Icon= gtk-dialog-warning
    : click "Add" button
    : Path= wipe
    : Parameters= -f -r -s %M
    : Select Conditions tab and click "Both"
    : Click OK > OK > Close
    ** A reboot may be required to see both options when right-clicking **

    • Varun Kashyap
      July 20, 2009 at 10:29 am

      Awesome, Good one Martin, Thanks for the info

  8. Chris
    July 20, 2009 at 9:53 am

    Killdisk from Active works like a champ for me each time. Dos based and windows based interfaces allow me to wipe drives how ever i like and how every many passes i like.

  9. venkat
    July 20, 2009 at 9:26 am

    eraser and dban are very useful to wipe out all data on hard drive.

  10. Matrik
    July 20, 2009 at 1:49 pm

    @Neo Recuva is a great program for recovering deleted files.