“I have several old computers that I would like to donate to school charities,” one reader wrote in an email. “I’ve erased the information on the hard drive, but I’ve heard that simply deleting data doesn’t completely remove it. Can you advise us on how to securely erase data from a computer?”
Unfortunately, you heard me right: Just because you’ve deleted a file on your computer and emptied the Recycle Bin doesn’t mean it’s gone forever. Ensuring these files are properly erased takes some extra work, but if you’re considering donating, selling, or even recycling an old computer with a hard drive inside, it’s definitely worth the time.
“There are so many stories about people buying used computers online and recovering data,” said Andrés Arrieta, director of consumer privacy engineering at the Electronic Frontier Foundation. “It’s kind of scary. It’s your whole life there.”
If you’re serious about protecting your data from potentially prying eyes, here’s how to securely erase your old hard drives.
For hard drives in a working computer
If you can actually start and use the computer you want to get rid of, consider yourself lucky. Luckily, with the right software, the process can be easy. Luckily, in some cases, the operating system that the computer is running already has everything you need to securely erase the hard drive.
- Click the Settings icon, then click Change PC settings.
- Click Update and Recovery followed by “Recovery”
- Under the Remove everything and reinstall Windows heading, click Get Started.
- When prompted, select the “Full wipe drive” option.
- Click the Windows button in the lower left corner and then click the gear-shaped settings icon
- Click Update & Security and then click Recovery in the sidebar
- Under Reset this PC, click Get started, then click Remove everything.
- When you get to the Additional Settings screen, click Change settings and make sure the options to Clean data and Delete files from all drives are checked
- Click the Windows button on the toolbar, and then click the gear-shaped settings icon
- Click Windows Update. Then click on Recovery and choose Reset your PC option
- Select “Remove everything” and click “Change settings” to ensure that the “Clean data” option is checked
For computers running even older versions of Windows—like Windows XP, Vista, or 7—you may need to look elsewhere for the right tools. The EFF also recommends using free apps like BleachBit and DBAN to securely erase individual files or entire hard drives.
These can also be useful if you are also using newer versions of Windows. These apps are good for dealing with particularly sensitive data that you want to erase, or if you want more control over how your hard drive is erased and overwritten.
- Turn on (or restart) your Mac and hold down the Command and R keys while it boots up – this will put your computer into recovery mode
- Sign in to your account (if necessary) and click Disk Utility
- Select the disk you want to erase and click Erase button
- Click Security Options and select how thoroughly you want the drive erased. Most people will choose the second option, which will overwrite all your saved data twice
For hard drives in a non-working computer
If one of the computers you want to responsibly get rid of won’t turn on, it might be a better fit for a trip to a recycling facility than an eBay buyer. But just because the thing won’t boot doesn’t mean the personal data stored on the hard drive is lost forever.
We must do something about this. And the first step is to access the disk itself.
For people who are familiar with the insides of a computer — or anyone who would like to poke around inside — one way is to open the PC and grab the hard drive. Don’t worry: it’s often a lot easier than it sounds.
Most desktop computers can be opened up quickly, and provided there aren’t many parts in the way, disconnecting the hard drive shouldn’t take much more than unplugging a few cables and removing a bracket. This process can be more difficult on laptops, so it’s a good idea to search for a repair guide or YouTube tutorial for your specific model before taking the plunge.
Once you’ve managed to free that hard drive from its metal prison, use a USB drive enclosure or docking station to physically connect it to another computer, where you can use the aforementioned software tools to erase it responsibly.
If this sounds like a pain, there’s still the easy way: you could take your device to a local repair shop, where they can pull the hard drive out in moments. (For all its quirks, Yelp is a helpful place to look for these shops.) You could probably safely delete it for yourself, too, which would save you even more time.
The Office Space approach
There’s also the low-tech – and some might say more therapeutic – approach. If you can physically remove your old hard drive from a computer you plan to recycle anyway, take the hard drive outside and give it a liberal dose of sledgehammer. A rock from your yard would also work, as would using a drill to poke four or five large holes around the center of the disk.
Really go with what feels right when the game’s name does some office space-style damage. (Just don’t forget the goggles.)
“If you were going to just throw it in the trash anyway, hammer it,” Arrieta said. “Why not have fun with it?”
Specifically, here we’re trying to dirty the drive’s platters, the spinning platters on which our data is meticulously magnetically placed. Destroying these disks will not always render your data completely irretrievable, but it does make the process of salvaging this information more trouble than it’s worth in all but the most extreme cases. (For example, if you hold government secrets, it’s probably better to shred the drive entirely.)
However, once you’ve had your fun, don’t just toss the broken drive in the trash — find a local e-waste facility and dump the carcass there.