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Published on 08.25.06 by Brent Trahan

How to Make Sure Your Deleted Files Are Completely Erased

Learn how to use the Cipher command included with Windows XP or as a download to completely erase deleted files.

You just deleted a few sensitive files from your computer and you emptied your recycle bin.  You assume those files are gone right?  No, they are still there.  The only thing that’s gone is the first letter of the file name. Deleted files can easily be recovered with the right tools.  This guide shows you how to use the cipher command (included in Windows XP) to write over empty space or deleted data three times so that no one can recover those files.

What Is Cipher?

Cipher is a utility that comes with Windows XP that writes over free space on your hard drive three times to make sure no one can recover files you’ve deleted.  This is a great tool to use when you get rid of a PC to make sure no one gets there hands on your stuff.

If you have a version of Windows that was released before Windows XP you can download Cipher from Microsoft.

How Do I Use Cipher?

The first thing you need to do is open the command prompt (DOS).  Click start, run, type cmd in the run box, then press enter on your keyboard.  You should have a black window open now.

Type cipher /w:C:\ in the command window and press enter on your keyboard.  This will write over all the free space on your C:\ drive three times.

You can substitute the C:\ in the cipher command to another drive or a path to a particular folder. An example of this is: cipher /w:C:\Documents and Settings\Administrator\My Documents\.

For a very detailed how-to on the cipher command, check out Microsoft’s Cipher Documentation.

Still need help? Ask your computer question now.

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10 Responses to “How to Make Sure Your Deleted Files Are Completely Erased”

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  1. VirkStar says:

    very usefull, i always wondered how to do that

  2. Al Sargent says:

    Thanks for this tip.

    My question is this: I’m running cipher /w as I write this. It’s been running for over ten hours, and I have no idea how long it will take to finish. Are there any rules of thumb for how long a typical PC will take to clear out one gig of disk space?

  3. Brent Trahan says:

    None that I know of. The amount of time it takes depends on the size and speed of your hard drive.

  4. elie says:

    Will it be easier to just fill up the whole hardrive with a large file (like a movie) and erase it ?
    Just curious, why would this Cypher function need to erase available space on the hardrive 3 times? Why 1 is not enough? DIGITS are either 1 or 0 !
    Any help is welcomed !

    • Joe says:

      The idea here is try to make it impossible to be able to recover the data. Even when you write over a bit on a disk, if you did enough analysis on the drive, you could find a very small difference because data was once there and then you could reconstruct the data by looking at these differences and determining what the bit used to read. It would take special tools since the difference is smaller then what normally would be detected. This is why they are overwriting three times. It makes it more difficult to reconstruct but I would guess still not impossible but out of reach for 99.9 percent of people to do. Think about some of the hard drives they recovered from the space shuttle that went down. These drives were toast – burned to a crisp. They still recovered a large amount of the data by doing the same thing. if you filled your hard drive a couple times, you could do the same thing, yes I think so. I started this command on a terabyte drive, trying to erase one directory that had about 220 gig in it.. its been running for a week now – still on the first pass. sucks. Simply writing 220 gig to that directory would not have wrote over the old data – so I would of had to write to the entire disk, But I could have done this three times by now at least. I’m not sure if I should blame the command or the external drive (that I want to return because it has problems which is why I am trying to erase the backup of my system in the first place). Hope this helps..if not you, someone else

  5. shwet says:

    Very useful article. For assurance you have erased your data, you need drive wipe tools because normal formatting doesn’t delete data complete or zero the data. These utilities rewrite the data so that it cldn’t be recoverable.

    Thanks

  6. Roy says:

    Thanks for the effort in publishing this for the benefit of others. I tried it too but the specific folder which i typed still contains the files which were deleted a year ago. This is really stunning. It sums up to about 1.4GB of my disk space. Im using vista. How can i get rid of this files which have already been deleted so long ago?

    Regards,
    Roy.

  7. Brent Trahan says:

    What happens when you delete the folder? Do any errors or messages pop-up?

  8. anon says:

    Wow… using cipher takes forever!! I am 1 hour in and am only at:
    “Writing 0xFF”
    ……_

  9. rice says:

    WELL…MINE ONLY TAKE 2 HOURS..
    Is that possible..but I only have my computer for 2 months..may be this is the reason.
    Just wondering can I able to restore the internet history after running cipher/w:c:\ ?

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