There comes a time when we all have to say goodbye to an older computer.
The lure of a newer and faster model is as inevitable as our next smartphone upgrade. But before you pass your old machine on to a worthy cause or take it to the local recycling centre, you need to make sure you have safely and securely removed the data from it.
Sensitive data can be easily recovered from old computer hard drives yet people still don’t get the message, often resulting in them passing on reams of potentially sensitive information on to complete strangers. By giving away your old drive, you could be giving away your bank details and much more.
What can you do to make your old computer safe before you dispose of it?
Simply deleting files is not enough because with the right tools it is possible to recover them from the hard drive. Whether you are looking to sell your iMac, MacBook or a Windows based PC or laptop there is plenty of free software available to help you recover files you’ve accidentally deleted, and there’s no reason why this can’t be used by the more unscrupulous.
How about if you format the disk? Sadly that’s not foolproof either, even after a format, traces of the data that was previously on the machine can remain and allow it to be recovered.
Fortunately, manufacturers are aware of the need to provide a means of deleting your data. Where in the past there was a ready market in safe deletion tools – and these are still available if you want them – popular operating systems now tend to have a safe means of wiping the machine built in. The key to making this work is that the data isn’t just deleted, the space that it occupied is overwritten with random information, making it impossible to recover.
Save your data
Before you leap in and wipe your old laptop, you must backup the information that is on there. You may have thought you’d transferred everything you need to your new system, but the chances are you’ll discover a few months down the line that you’ve forgotten something essential.
You can take a backup to an external drive, Windows systems have a backup tool built in, or you can copy your files to a cloud service such as Dropbox. The advantage of the latter is that installing Dropbox on your new machine will automatically sync all the data back again without your needing to copy it. Another way to use storage tools like Google Drive; after you have synced your data, you can go back onto your Drive and permanently delete your Google files and history for maximum security.
On older Windows systems, XP, Vista or Windows 7, you’ll need a third-party tool to securely wipe data. There are plenty of these available if you search reputable freeware directories. Tools such as DBAN allow you to create a bootable CD or flash drive. Start the machine from this and follow the instructions to securely wipe the hard disk contents. Because DBAN boots independently of the operating system, it can be used on any Windows system as well as on machines running other systems such as Linux.
From Windows 8 onwards, Microsoft has built a disk wiping facility into the operating system. On Windows 8 or 8.1 systems go to Settings from the Charms bar and select Change PC Settings. From there choose Remove Everything and Reinstall Windows, make sure you select the ‘Thoroughly’ option rather than ‘Quickly’ as this ensures the disk is fully erased before Windows is reinstalled. At the end of the process you then have a machine with a fresh install of Windows that you can safely dispose of.
Windows 10 systems are similar, go to Settings from the Start button menu, choose Update & Security, followed by Recovery. From there you have the option to reinstall Windows, make sure you choose Remove files and clean the drive. If your laptop has multiple drives you will be asked if you want to clean the others too. Select this option if you don’t intend to keep the machine.
Mac systems have a similar procedure. For pre Lion or Mountain Lion systems, you’ll need to have your system disk handy. Hold down Command and R as the machine boots to open the recovery partition, then select Disk Utility. On the Erase tab select 7-pass Erase, this will overwrite the data several times. It will take a long time but is very secure.
If you can’t access the computer’s hard drive – the system won’t boot for example – it’s not safe to assume the data can’t be recovered. In this case, it’s best to physically remove the hard drive from the PC. Putting the disk near a strong magnet, hitting it with a hammer, or removing the cover to expose the platters to air should be enough to render it unreadable.