Start by encrypting, then reset
On a modern Windows machine this is the fastest reliable route, and it works on both an SSD and a mechanical drive.
- Turn on BitLocker (Settings → Privacy & security → Device encryption, or Manage BitLocker on Pro editions). Let it finish encrypting.
- Go to Settings → System → Recovery → Reset this PC.
- Choose Remove everything, then Change settings, and turn Clean data on.
- Let it run. Once the encryption key is discarded, what remains on the platters or cells is ciphertext with no key.
This is why it works: you are not trying to overwrite every byte, you are destroying the only thing that made those bytes readable. It is quick even on a large drive.
If the drive is out of the machine
A bare drive on a bench is a different job, and the right tool depends on what kind of drive it is.
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Mechanical hard drives
A single full overwrite is enough. In an elevated Terminal:
diskpart, thenlist disk,select disk N, thenclean all. Check the disk number twice; there is no undo. -
SSDs and NVMe drives
Use the manufacturer's tool instead. Samsung Magician, Crucial Storage Executive, WD Dashboard and Seagate SeaTools all expose the drive's own secure-erase command, which is the correct instruction for flash. Why an SSD is different →
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Any drive you cannot boot
Leave it. Bring it in and we will erase it here.
One full pass is sufficient on a mechanical drive. The thirty-five-pass routine people still cite was written for 1990s encoding and has not been necessary for a very long time.
The two methods that do not work
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Deleting the files, or emptying the Recycle Bin
This removes the pointer, not the data. The longer explanation is here.
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A quick format
It rebuilds the index and leaves the contents in place, which is why recovery software finds so much after one.
Both are worth knowing about because both are what most people mean when they say a drive has been wiped.
What not to do if you want to sell it
Drilling a drive, hammering it or taking a magnet to it destroys the value along with the data, and none of those is more thorough than a proper erase.
Failed drives are not purchased at all, and a drive you have physically damaged is a failed drive. If the data genuinely warrants destruction rather than erasure, keep the drive and sell the machine without it — the offer is lower, but that is a straightforward trade.
What we do regardless
Whether or not you wiped it first, every drive we buy is securely erased here at no charge. Ask and you get a printed Certificate of Data Destruction before you leave; it is free, but it is issued on request rather than automatically.
We do not check what was on it and we do not read it. What we do record is the model and serial of what we bought, and the ID of the person who sold it, which is a condition of dealing in secondhand hardware.
Common questions
Should I wipe it before bringing it in?
You do not need to. If you would rather, the encrypt-then-reset route above is the one to use, and we will still erase it again afterwards.
Can I watch you erase it?
Yes, on request. Erasure happens after the purchase is complete rather than during the evaluation, so tell us at the start that you want to see it and we will arrange it. Note this is different from the bench testing, which customers cannot attend.
What if the machine will not turn on?
Bring it. We can erase a drive out of a dead machine, and the machine is still worth something for its parts.