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What’s on your old hard drive? ‘Delete’ does not mean destroy

Have you ever sold an old computer? Given it to charity? Or sent it to the scrapheap? If so, you could be among thousands of Brits who may have unwittingly put their personal data at risk in the process.

It’s a common misconception that ‘delete’ means ‘destroy’. In fact, with just a little expertise, deleted files can easily be recovered from old hard drives.

In an investigation conducted by Which? Computing, we purchased several second-hand hard drives online via eBay – some cost as little as £15 to pick up.

Using the kind of data recovery software that can be cheaply downloaded off the internet by anyone, we were able to recover over 2,500 files from the eleven hard drives we’d purchased. We recovered everything from personal photos, spreadsheets, music files to online chat conversation histories.

Our lab experts conducted this exercise under tightly-controlled conditions, and the recovered data was fully destroyed at the end of the investigation. But in the wrong hands, the same data could lead to ID theft, fraud or even blackmail.

The risks of recovered data

Have you ever saved a CV on to your computer’s hard drive? Ever done your online banking on your home computer, or saved copies of documents to do with your home finances? These are exactly the sorts of files that can be retrieved from an old hard drive if all precautions aren’t taken to destroy the data properly.

In our recent survey of 1,003 Which? readers, we found that many are potentially leaving themselves at risk when disposing of old computer equipment. Of those who had ever sold or recycled a computer, 53% deleted their files first, though only 38% said they’d emptied the Recycle Bin as well.

Crucially, only 43% of the respondents had removed a computer’s hard drive before disposing of it. When you’re dealing with your own private files, this is the most secure method of all for ensuring no one can recover your own data from your old computer.

Data destruction – how do you do it?

Keeping a library of old hard drives stored away at home may seem like a pain, but it beats the risk of leaving your files on an old hard drive when disposing of an old computer.

Alternatively, data-wiping software can help to permanently over-write your files, though this can often be complicated to use for the less computer-savvy.

The safest method of permanent destruction is to remove a hard drive and take a hammer to it until the disk is smashed to smithereens. Environmentally this isn’t great, and it can prove hard work, but it certainly makes things nigh-on impossible for data thieves.


Personally I have always found driving a 6″ nail though the drive platter does the job pretty well, all considering.

dfdf says:
16 January 2013

To erase data permanently on disks with bad sectors, try WBD(Wipe Bad Disk).

John Cannell says:
16 January 2013

As mentioned earlier, unless you’re destroying a business HD, where security is of great importance an easier way for domestic use is Ccleaner, a free download from here:-
which has many useful features for the home user, including ‘drive wiper’, which deletes and then overwrites the deleted files. (Delete just means that the files can be overwritten – the data is still there until it IS overwritten.) It can overwrite several times if required. It can be programmed to act on just deleted and empty areas of the drive, or all of it. This should be sufficient in most cases.

Neo Jensson says:
18 December 2013

One way to erase data from hard drive is ErAce. It over writes har drive 1-100 times. In that way it is impossible to recover data. It can be loaded from erace.it or sourceforge

Michael Williams says:
11 February 2015

I have an old computer that I’m trying to sell. However, I’m not sure that I’ve fully wiped the hard drive. I know that a lot of people say that nothing is never lost on the net, but I really want this to be. Do I have to completely destroy the hard drive, or what are my other options?

Hi Michael, your other options are to simply remove the hard drive and put it in a safe place in your home or if you have the Windows installation disk for this machine go through the Windows re-installation process including a full format of the drive. Personally I’m not a fan of smashing things up as this can be dangerous unless you wear proper protective clothing such as thick gloves and eye protection!

Yes, it is true, permanent data wiping can be done by various techniques. Most of them are undermentioned

1) Crushing/Physical Destruction
2) Shredding
3) Degaussing
4) Using Data Erasure Tool

Different people use different methods for data erasing depend on their situation and understanding. But, personally being pro-environment-friendly. I always opt for method which creates less or no pollution. Used various data erasure many times in past, some of them are BitRaser, DiskWipe, Eraser. All of them works well and destroys all HDD sensitive data. But BitRaser software gives me more satisfaction in terms of Certifying about complete removal after recovery.
The last technique is no doubt a eco-friendly technique. Choose wisely

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