How Do You Securely Wipe a Drive Before Selling?

Sourced from real discussions on r/DataHoarder and r/techsupport, cross-checked against live PricePerGig listings.

When selling hard drives, or even just giving them to be reused, you should always always securely delete the data. Think of all the files you’ve had on there? Emails, random bank application files, your holiday details for next year downloaded with just those three I can see where you have accounts for me to access, call your bank and get card reissued (maybe, maybe not these days) and call my local (or not so local) criminal friend to burgle you while you’re away, and those are just the things I can think of, I’m sure there are many more.

BEFORE you delete everything, here’s a quick checklist though, maybe there are some important things you’ve left on the drive you forgot about?

We’ve all heard of the guy who threw out 1000’s of bitcoin, so I’d check for that first, but here is a full list of things to search for before you wipe it.

• Files: wallet.dat, *.kdbx, id_rsa, id_ed25519, *.pst, *.ost, *.pfx, *.p12, *.vmdk, *.vhdx, *.psd / *.flp / *.als / *.prproj, and anything named seed, mnemonic or recovery
• Folders: .git, DCIM, seed / mnemonic / recovery

Ok, onto how to do it. On Windows, Eraser is a long standing free tool that overwrites files or whole drives from inside Windows itself. On Mac and Linux, or any machine you can boot from a USB stick, ShredOS boots straight into a wiping tool and scrubs the whole drive with no operating system needed. For an SSD, use the maker’s own toolbox and its Secure Erase button instead, as covered below.

The table above shows live prices for hard drives of 6TB and up on your marketplace for the upgrade you are funding by selling the old one.

Why deleting is not enough

This trips up so many people, so let me be blunt.

When you delete a file or quick format a drive, the data is not erased. The system just forgets where it is and marks the space as reusable.

Until something overwrites it, the data is fully recoverable with tools anyone can download.

So that drive you are about to post to a stranger still holds your photos, documents and logins, just out of plain sight. Wiping properly is the only way to actually remove them.

Wiping a spinning hard drive

For a normal hard drive, the method is simple: overwrite every sector.

A single full pass that writes zeros across the whole drive is enough on any modern drive. The old myth about needing many passes is just that, a myth.

You can do this with a built in disk tool or a free disk utility that offers a full erase or full format (not quick). Let it run, and when it finishes, every sector has been overwritten and the old data is gone.

It takes a while on big drives. That is normal. Let it finish.

Wiping an SSD: use Secure Erase

SSDs need a different approach, and this is important.

Because of how SSDs shuffle data around internally, a plain overwrite does not reliably hit every cell. The right tool is the drive’s built in Secure Erase command.

Most SSD makers provide a toolbox app with a Secure Erase button, and many motherboards have the option in the BIOS. It resets all the flash at once, wiping everything cleanly and instantly.

So for an SSD, reach for Secure Erase, not a manual overwrite.

A safety net before you wipe

One obvious but vital step.

Before you wipe anything, make sure everything you want is safely copied elsewhere. A wipe is final.

Check your backup, confirm your important files are somewhere else, then wipe with confidence.

The bottom line

To sell a drive safely, never rely on delete or quick format. Overwrite a hard drive fully with a single pass, or run Secure Erase on an SSD, and your data is genuinely unrecoverable.

Back up first, wipe properly, then sell or pass it on with peace of mind. Use the live prices above to pick the replacement your old drive just helped pay for, and enjoy the clear conscience.

So now you’ve backed up even the files you’ve forgotten about, securely deleted the data, go sell it on eBay or gift to a friend, but you could also just keep it as proper offsite backup.

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