How to Wipe a Hard Drive Before Selling or Recycling It (Windows & Mac)

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Selling, donating, or recycling an old computer is a smart move, but the drive inside it remembers everything. Dragging files to the trash or running a quick format only removes the index that points to your data, not the data itself. Free recovery software can bring deleted tax records, saved passwords, and personal photos back in minutes. Before any drive leaves your hands, it needs a proper wipe that overwrites the data or destroys the encryption keys protecting it.

This guide walks through wiping a hard drive or SSD the right way on both Windows and Mac, using tools already built into each system. The process takes a few clicks and some patience, and it protects you from the most common source of second-hand data leaks. Start by backing up your PC to an external hard drive, because once the wipe begins there is no undo.

Step 1: Back Up and Sign Out of Your Accounts

A few minutes of preparation prevents the two most painful outcomes: losing files you meant to keep, and shipping a machine that is activation-locked to your account.

1. Copy your documents, photos, and browser bookmarks to one of the best external backup drives or a cloud service, then open a few files from the copy to confirm the backup is good.
2. Deauthorize software tied to the machine, such as iTunes, Adobe apps, and any license-limited tools, so you can activate them on your next computer.
3. Sign out of your Microsoft, Google, and Apple accounts, and turn off Find My on a Mac. Activation locks can make a wiped machine unusable for the buyer.
4. If you are upgrading rather than selling, you may prefer to clone the old drive to an SSD before erasing the original.

Step 2: Wipe a Drive on Windows 10 or 11

For the drive Windows runs from, the built-in reset tool does the whole job, including the overwrite.

1. Open Settings, go to System, then Recovery, and click Reset this PC.
2. Choose Remove everything, then pick either Local reinstall or Cloud download.
3. Click Change settings and switch on Clean data. According to Microsoft’s documentation, this option overwrites the drive rather than just deleting files, which is exactly what you want before a sale. Expect it to take several hours.
4. Confirm and let the reset finish. The PC will restart at the Windows setup screen, ready for its next owner.
5. For a secondary or external drive, open File Explorer, right-click the drive, choose Format, and untick Quick Format so Windows overwrites the full disk. A quick format is fine for drives you are keeping, as covered in our guide to formatting an external hard drive, but a full format is the minimum before a drive changes owners.

Step 3: Wipe a Drive on a Mac

1. On an Apple silicon or T2-equipped Mac, open System Settings, go to General, then Transfer or Reset, and choose Erase All Content and Settings. Per Apple’s documentation, this destroys the volume’s encryption keys, which makes the data unrecoverable in one quick step.
2. On an older Intel Mac, restart and hold Command-R to boot into macOS Recovery.
3. Open Disk Utility, click View, choose Show All Devices, and select the top-level drive rather than a volume under it.
4. Click Erase, name the drive, and pick APFS (or Mac OS Extended for a mechanical drive) with a GUID partition map.
5. On mechanical drives, click Security Options and move the slider at least one step to the right so Disk Utility overwrites the old data during the erase.

Step 4: Wipe an SSD the Safe Way

SSDs store and shuffle data differently from mechanical drives, so repeated overwriting adds wear without guaranteeing every cell is cleared.

1. Use the drive maker’s utility, such as Samsung Magician, Crucial Storage Executive, or WD Dashboard, and run its Secure Erase or Sanitize function following the manufacturer’s documentation.
2. Alternatively, encrypt the drive first with BitLocker or FileVault, then erase or reset it. Deleting the encryption key leaves only scrambled data behind.
3. Verify the result by connecting the drive to another computer. It should appear empty or unformatted, with none of your old volumes visible.

Common Mistakes to Avoid

The most frequent error is stopping at a quick format or a simple file deletion, both of which leave data easily recoverable. Another is wiping the wrong disk: double-check drive letters and capacities before confirming, because the erase happens immediately. Skip old multi-pass military wipe routines on SSDs; they add wear and, per drive manufacturers, a single secure erase is sufficient. Do not forget activation locks, since a buyer cannot set up a Mac or PC still tied to your account. Finally, if you keep copies of sensitive documents, store them on one of the best encrypted USB flash drives rather than an unprotected disk in a drawer.

Frequently asked questions