How can I safely clean my hard drive?

Are you selling or giving away your computer? You may have erased your private data by deleting files and reinstalling Windows, but you’re not quite done yet. The last action you need to take before saying goodbye to your old friend is wipe the hard drive clean.

Most computers now come with solid-state drives (SSDs), which are faster than their mechanical counterparts but can be trickier to wipe. Simply deleting your files doesn't do the trick since they can be restored from the Recycle Bin. And even if you empty the Bin, your deleted files can often be recovered with the right utility. 

Regardless of what version of Windows you are running, you can reset the OS to factory conditions using built-in reset features. However, a good hard drive eraser utility will be needed if you want a stronger and more secure method of wiping your drive.

Wipe Your Drive in Windows 10

I've been working for PCMag since early 2016 writing tutorials, how-to pieces, and other articles on consumer technology. Beyond PCMag, I've written news stories and tutorials for a variety of other websites and publications, including CNET, ZDNet, TechRepublic, Macworld, Popular Science, Time, Fortune, US News & World Report, and AARP Magazine. I spent seven years writing breaking news for CNET as one of the site’s East Coast reporters. I've also written two books for Wiley & Sons—Windows 8: Five Minutes at a Time and Teach Yourself Visually LinkedIn.

Since the Help Desk launched last year, we have received loads of requests for the best ways to preserve different kinds of data in our lives, such as voice mails, conversations and even cherished home videos.

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Judging by the state of our shared inbox, though, the opposite is also true. Many of you are just as eager to find out how to make some of your data disappear entirely, whether it is splashed across social media or locked up in old hard drives sitting around the house.

“I have several old computers that I would like to donate to charitable organizations for schools,” one reader wrote in an email. “I have erased the information on the hard drive but have heard that simply deleting data does not remove it completely. Can you advise how to securely wipe data from a computer?”

Unfortunately, they heard right. Just because you deleted a file on your computer and emptied the recycle bin does not mean it is gone forever. Making sure those files are properly gone will take some extra work, but if you are considering donating, selling or even recycling an old computer with a hard drive in it, it is absolutely worth putting in the time.

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“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 is kind of scary. It is all your life there.”

If you are serious about keeping your data away from potentially prying eyes, here is how to securely erase your old hard drives.

For a working computer

If you can actually fire up and use the computer you want to get rid of, consider yourself lucky. With the right software, the process can be mercifully simple. Thankfully, in some cases, the operating system that runs the computer already has everything you need to securely erase the hard drive.

Windows 8.1

• Click the Settings icon, then click “Change PC settings.”
• Click Update and Recovery, followed by “Recovery.”
• Under the heading “Remove everything and reinstall Windows,” click “Get started.”
• When prompted, select the option “Fully clean the drive.”

Windows 10

• Click the Windows button in the bottom corner, then the Settings icon.
• Click Update and Security, then “Recovery” in the sidebar.
• Under “Reset this PC,” click “Get started,” then “Remove everything.”
• When you get to the “Additional settings” screen, click “Change settings” and make sure the “Clean data” and “Delete files from all drives” options are enabled.

Windows 11

• Click the Windows button in the toolbar, then the Settings icon.
• Click on Update, then “Recovery” and select the “Reset PC” option.
• Choose “Remove everything,” then click “Change settings” to make sure the “Clean data” option is enabled.

For computers running older versions of Windows like XP or Vista, you may need to turn elsewhere for the right tools. The Electronic Frontier Foundation also recommends using free apps like BleachBit for securely erasing individual files.

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These can also come in handy if you use more recent versions of Windows. These apps are suited for dealing with especially sensitive data you want gone or when you want more control over the way your hard drive gets wiped and overwritten.

Mac systems

• Turn on or restart your Mac, then hold down the Command and R keys while it boots to bring your computer into recovery mode.
• Log into your account if needed and click the “Disk Utility” icon.
• Select the hard drive you want to wipe and click the “Erase” button.
• Click “Security Options” and select how thoroughly you want the drive to be erased. Most people will be fine selecting the second option to write over all of your saved data twice on the system.

For a nonworking computer

If one of the computers you are looking to get rid of responsibly does not turn on, it may be better suited for a trip to a recycling facility than to an eBay buyer. But just because the thing does not boot does not mean the personal data stored on its hard drive is already lost to the ages.

We are going to have to do something about that. And the first step is gaining access to the hard drive itself. For folks familiar with the inside of a computer, or anyone eager to poke around in there, one approach is to crack the computer open and grab that hard drive. No worries, because often enough, this is much easier than it sounds.

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Most desktop computers can be opened quickly and, assuming there are not a ton of parts in the way, disconnecting the hard drive should not involve much more than unplugging some cables and removing a bracket. This process can be trickier for laptops, so it would be a good idea to search for a repair guide or a YouTube tutorial for your specific model before taking the plunge.

Once you have 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 software tools mentioned earlier to responsibly erase them.

If this sounds like a pain, there is always the easy way. You could take your machine to a local repair shop where they could pop out that hard drive in mere moments. For all its quirks, Yelp is a helpful place to start looking for these shops. They could probably also securely wipe it for you too, which would save you even more time.

The ‘Office Space’ approach

There is 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 drive outside and apply a liberal dose of sledgehammer to it. A rock from your garden would also work, as would using a drill to make four or five big holes around the center of the hard drive.

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Really, go with whatever feels right when the name of the game is doing some damage like “Office Space.” Just remember the safety glasses. “If you were just going to throw it in the trash anyway, sure, hammer it,” Arrieta said. “Why not have fun with it?”

What we want to do here is foul up the hard drive platters, the spinning discs that our data is meticulously placed upon. Destroying these platters will not always make your data completely irretrievable, but it makes the process of salvaging any of it more trouble than it is worth in all but the most extreme cases. If you have government secrets, for instance, you are probably better off shredding the drive entirely.

Once you have your fun, though, steer clear from tossing that busted drive in the trash. Find a local electronic waste facility and drop off its carcass there.

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