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I'm about to give away an older computer with just the Windows XP operating system intact and all other programs uninstalled. However, upon peeking at the "free space" with software called "Recuva", I notice lots of deleted things that could be recoverable. Some of these include sensitive data files, pdfs, and other personal items that I would not want retrieved.

I ran a program called "Eraser" to try and overwrite that data, but it failed to do an adequate job. I also tried to do the job with "Glary Utilities" but it failed too.

Short of installing a new, very cheap hard drive and re-installing the bare bones operating system, I'm out of ideas.

EDIT - WOW!!! I was not really expecting this many GREAT ideas. My next question is this. If I go the DBAN route and truely wipe the hard drive, then restore my disc image (I use Acronis True Image) will it also restore the free space data? Does imaging just copy readable data? I have an old image of when the OS was first installed.

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To (try and) answer your edit question- I <i>think</i> that the image will be written to the <b>required</b> hard drive space. As in, you should still wipe the free space. Willing to be told otherwise though! (Not sure if html tags work here..?) –  outsideblasts Nov 25 '09 at 2:32
    
No they don't... –  outsideblasts Nov 25 '09 at 2:33
    
@outsiteblasts: you can use a * instead of <b>. See superuser.com/editing-help –  Greg Sansom Mar 17 '11 at 23:35
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12 Answers

up vote 7 down vote accepted

I have seen many utilities that can overwrite just free space, but I have never had good experiences and like you, they seem to fail.

What I recommend you do is use some sort of backup / imaging software and take a copy of everything on your machine then use something like DBAN to truly wipe the hard drive then restore your backup to the drive.

This should do the job fine!

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+1. this is what i'd do too. DBAN the drive, then do a fresh install of XP. (restoring a backup is fine too, but if you haven't done a fresh install or restore-to-factory-OS you might have left some personal stuff around in actual files, which would then get restored... so i'd see the fresh install as preferable.) –  quack quixote Nov 24 '09 at 17:57
    
+1 agreed... I just thought he really didn't want to reinstall Windows –  William Hilsum Nov 24 '09 at 18:08
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@Wil - This gets the checkmark because I see it as the best, safest option. I'll DBAN the hard drive, then restore the image I have that was done right after the original OS install. Thanks to everyone for all the great answers. It was hard to choose a winner. –  Patriot Nov 25 '09 at 4:22
    
+1 thanks for picking me! –  William Hilsum Nov 25 '09 at 4:53
    
@Patriot DBAN takes way to long and doesn't completely wipe the drive. Use MHDD to secure erase it 0's out the drive and does it very quickly if anyone says that's not enough they need to do some research on the subject. –  Arctor Mar 17 '11 at 23:57
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Ccleaner also has a "Wipe free space" facility. I presume that it does your job, and I presume that it leaves everything intact. But I don't know how secure it is.

alt text

"You can set CCleaner to wipe the free areas of your hard disk so that deleted files cannot be recovered."

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Wiping Free Disk Space explained: docs.piriform.com/ccleaner/using-ccleaner/… –  Chris Nov 24 '09 at 19:43
    
Thanks Chris. Just added that after you did! –  outsideblasts Nov 24 '09 at 19:46
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Sysinternals SDelete. All it does is generate a free-spaced sized file full of junk (or zeros, depending on settings). It gets most all of the free space (I imagine it must miss a few blocks), and it's free. If you put it into the mode where it just writes zeros (instead of multi-pass junk), it's not too slow.

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All you need to do is create a bunch of big files that take up all of your free space, then delete them. I'm pretty sure that's how Eraser works. Or if you want random data for some paranoid reason, grab Truecrypt, have it create an encrypted file that's close to the size of your free space (you don't want to fill it all or the computer won't work), and then let it do it's drive randomizer thing.

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On Linux all you to do is run dd if=/dev/urandom of=file & rm file (preferably while nothing is running) –  Brendan Long Mar 3 '10 at 3:20
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Free File Shredder :

Shred Free Disk Space - This option will shred unused or free disk space across the whole disk volume. For instance, this option is very useful if you haven't shred your unwanted files regularly but instead you used regular windows delete command and now you want your previously deleted files unretrievable. Those files now can not be shredded by picking them since they are already deleted. This option will enforce shredding of everything you have deleted once using the regular delete command, whether it was yesterday or months ago.

Hard Disk Scrubber :

Summit's Hard Disk Scrubber is a Free secure delete program designed to help you permanently destroy sensitive data from your PC. Use Hard Disk Scrubber to overwrite free space on your Windows drives, or to permanently delete files so that they can no longer be recoverred.

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You could always use something like DBAN to wipe it clean completely, then re-install the bare bones operating system, rather than buying a new hard drive.

If you don't want to completely wipe out the hard drive, you can try out the SysInternals utility SDelete which has some options to wipe free disk space

SDelete.exe -z

The SDelete route may not be quite as secure, but will probably still do a satisfactory job and it is much simpler to use than having to DBAN the hard drive and reinstall.

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Cipher comes as part of Windows XP:

cipher /w:<Drive Letter>:

/W Removes data from available unused disk space on the entire volume. If this option is chosen, all other options are ignored. The directory specified can be anywhere in a local volume. If it is a mount point or points to a directory in another volume, the data on that volume will be removed.

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Eraser has features to wipe blank space, either securely, or with a single pass of zeros.

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A wipe with something like DBAN is the best option, followed by a re-install if you want the recipient to have a working OS installation.

If that's too involved or overkill, grab ccleaner and bcwipe. Nuke all of your personal files by hand, run ccleaner to clean out browser caches and other droppings Windows leaves around, then bcwipe your free space and swap file. No need to go all DoD paranoid -- a single overwrite will suffice, unless you're afraid of the NSA or the mafia. Then defrag your drives, then go through the BCwipe one more time for good measure. This will be a reasonable set of steps for the average person.

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A variation on dban for those of you who are especially parnoid

Encrypt the disk using the standard MS encryption software which uses a special key unique to each instance of XP and user (Right click the folder/ Properties / Advanced / Encrypt contents to secure data)

Then DBAN the entire disk, wiping out the key in the process.

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create a batch file and three files with zeros, copy two into the other then copy one of the first two and copy again, set the batch file to run until error, after error, delete the files and ring the bell to let you know it finished.

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At first remove your old restore points in your windows. This may keep old files that you deleted. Tools that clean free space have no chance to clean this files, until they are freed by removing restore points. After this use tools that remove old template files. there are two location. one is system temp directory under c:\windows , and second are users temp directories under his profile directory. you can reboot computer and remove them manually, or you can use tools like ccleaner. after that cleaning you can trully clean free space. what software you can use, this is explained by other posters in this discussion :) remember about emptying trash.

for paranoids. of course as jim say, you can remove swap file and hibernate file if you are use them, for clearing temporarly stored data under that files. then you do cleaning without swap/hibernate files. But there are lot of your personal data under your profile directory. I recommend create additional admin user, check this work, and completly remove previously used user profile. after this you must check 'user and settings' directory, then if anything exist that was used by removed directory, remove this completly. after that paranoid actions you can clean free space :)

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