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Will securely deleting recoverable files leave my actual files intact?

I pulled up a list of over 2600 deleted files with the Recuva program and I
would like to securely delete all of the files I’ve deleted. I have the option
to select all of the files at once, but many of the files I’ve deleted have been
overwritten by files I want to keep: program files, document files, etc. If I
choose to securely overwrite the whole lot, will I lose the files I want to
keep or will they remain intact? In other words, will Recuva securely delete
only those deleted files that have not been overwritten by the program and
document files?

In this excerpt from
Answercast #82
, I look at securely deleting files off a hard disk and if
that will overwrite any files that have been newly written to the space.

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Deleting recovered files

My understanding is yes, Recuva will do what we would consider the “right thing.” It will overwrite only those portions of the files that have not already been overwritten by some other program.

In reality, I would probably end up using a different utility for this. Recuva is great; I mean it’s wonderful for showing you exactly what kinds of things might be recoverable on the hard drive – but in reality, what I would do is I would go out and get CCleaner from the same folks – Piriform.

It has what’s called a free space wiper. It doesn’t try and delete or overwrite files on a file-by-file basis. It simply says, “Okay, we’ll look at the hard disk – and for all of the space that isn’t currently being used by an actual file; I’ll go out and overwrite that. In fact, I can overwrite it several times if you’d like for extra security.”

Securely cleaning files

On hard drives, if you’re extra paranoid, overwriting it a couple of times certainly can help prevent some fairly extreme data recovery techniques.

So, I would run that and use that to overwrite and clear off the free space.

After you do that, if you run Recuva again, it should show you nothing. It should say that there are no recoverable files once the free space has been overwritten.

There’s another utility also called SDelete. If you’re more of a command line person, like I am, it is a command line utility available from Microsoft for free.

It’s intent, its primary purpose, is to securely delete a file. In other words, you delete the file and then immediately overwrite the sectors on the disk where that file’s data had been contained – so that you don’t have to worry about it possibly being recovered later.

It also happens to include a free space wiping option as well. You can actually do that from the command line – or if you are extra concerned, you could even use that command line utility in a batch file that you run perhaps overnight.

(Transcript lightly edited for readability.)

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2 comments on “Will securely deleting recoverable files leave my actual files intact?”

  1. Not all of the files will be recoverable by Recuva. It might be an idea to rank them according to the degree of recoverability, and see how many in fact are deemed “Excellent”. As long as the rest are not patently and obviously sensitive, one could concentrate on just the “Excellent” category, hoping for only a small fraction of 2600.

    Should there be a chance of the drive ever being examined by professionals, I should not take any chances but back up, wipe it clean (DBAN), and reinstall the OS. A tight ship would have to be run from then on, understandably, not to have to go through a similar exercise again.

    Reply
  2. Hi Leo. I tried CCleaner to wipe the free space and I hate it. It reduced my original empty space available by 60 Gigs and the laptop Toshiba had a fit and told me I had run out of space!!! So this tells me that all the space I overwrote was then blocked by whatever CCleaner did and informed me it was un-available. So lesson learned is that it is better not to bother.

    I can only presume that something else happened here. Wiping free space should in no way cause that free space to be considered “used”. The only scenario I can think of with CCleaner is if it were interrupted before it was done, even then it should be able to clean up after itself. I’ll point you at this article to determine exactly where that formerly free space went: Where’s my disk space going?

    Leo
    03-Jan-2013
    Reply

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