How to wipe a laptop before selling it

Before a laptop leaves you, whatever is on the drive should stop being readable. That is not the same as deleting your files, and it is not quite the same as a factory reset either. Here is what actually works, for Windows and for macOS, and what to do when the machine will not turn on.

First, get your things off it

Anything that exists only on that laptop — photographs, documents, tax records, the folder nobody has opened since 2019 — needs copying somewhere else before you start. Once the drive is erased properly it is gone, which is the entire point.

Second, unlink it from your accounts

This step is separate from wiping and is not done by it. Erasing a drive does not release an activation lock or remove a device from your account, and a machine still tied to somebody’s account can be unusable to the next owner.

• Apple: sign out of iCloud, then turn off Find My and Activation Lock.
• Microsoft: remove the device from your Microsoft account and deactivate any linked licences.
• Google: sign out of Chrome and remove the device from your account.
• Work machines: the laptop may be enrolled in mobile device management. Only your IT team can release that, and until they do the machine will keep trying to re-enrol.

Windows: reset with the drive cleaned

Windows has this built in. Open Settings → System → Recovery and choose Reset this PC. Select Remove everything, then when it asks about the drive choose the option to clean the drive rather than simply removing your files.

That distinction is the whole thing. “Just remove my files” is quick and leaves data recoverable. “Clean the drive” overwrites it, takes considerably longer, and is the option to pick when the machine is leaving you.

macOS: erase all content and settings

On any reasonably recent Mac, open System Settings → General → Transfer or Reset and choose Erase All Content and Settings. This signs you out, releases Activation Lock and erases the data in one pass.

Macs with Apple silicon or a T2 chip encrypt the drive by default, so erasing the encryption key makes the previous contents unreadable without overwriting every block. On much older Macs you will need to boot into Recovery and erase the disk from Disk Utility instead.

Solid state drives are different

The old advice about overwriting a disk several times comes from mechanical drives. SSDs move data around internally for wear levelling, so repeated overwriting is neither necessary nor entirely reliable. The built-in reset options above are the right tool, because they trigger the drive’s own secure erase rather than writing over it from outside.

What if it will not turn on?

Then it cannot be wiped in the normal way, and this is where a lot of people give up and put the machine in a drawer permanently. Two options remain: have the drive removed and erased separately, or have it physically destroyed.

What you should not do is throw it away intact on the assumption that a dead laptop is a safe laptop. The drive usually still works perfectly well when moved to another machine, which is exactly how data comes off a laptop somebody believed was broken.

Do not take the drive out just to be safe

It is a understandable instinct and it costs you money. A laptop missing its drive is worth less than the same laptop with the drive wiped, because the buyer now has to source a replacement. If the data is the worry, say so at enquiry stage instead and have it dealt with properly — eligible storage is erased and a certificate is issued, and anything that cannot be wiped is destroyed rather than passed on.

If this is company equipment

A business needs more than a wiped machine: it needs to be able to show what happened. That means a record of which devices were processed and documentation recording the erasure, kept with your own asset records. Doing it device by device on a kitchen table does not scale past about five machines, which is the point at which handing the whole job over becomes the sensible answer.