Securely Erase Used Data Drives

Formatting alone is often not enough before disposing of or selling storage media. This article explains the differences between HDDs, SSDs, USB drives and SD cards and which erase method makes sense.

Sooner or later almost everyone faces the same question: what should I do with old hard disks, SSDs, USB drives or SD cards when I want to sell or dispose of them?

Simply formatting is not enough. Depending on the storage medium, data may still be recoverable. The decisive factor is therefore not the operating system, but the right method for the specific type of storage.

Why formatting is not enough

Formatting usually removes only file references. The actual data often remains and can be made visible again with tools.

HDD vs. SSD: the crucial difference

HDD

Classic hard disks store data magnetically. Targeted overwriting works reliably here.

SSD / Flash

SSDs, USB drives and SD cards use Wear LevelingWear leveling distributes writes evenly across an SSD so it lasts longer, but it also makes secure erasure more complex.

More in the IT glossary ->. Data is distributed internally, so simple overwriting does not reliably reach all areas.

Securely erase HDDs: how many overwrite passes?

Old recommendations such as 7 or 35 passes are no longer necessary today.

1 pass → sufficient for private use
3 passes → conservative standard
more → no practical added value

There is no fixed EU standard. In practice, 1 to 3 passes are considered secure.

Linux

sudo shred -v -n 3 /dev/sdX

Windows

cipher /w:C:

or tools such as DBAN or Active KillDisk.

macOS

diskutil secureErase 0 /dev/diskX

What is Secure Erase?

Secure EraseSecure Erase is an erase command executed directly by the storage device, resetting all storage areas reliably.

More in the IT glossary -> is an ATA/NVMe command executed directly by the storage device controller. It resets all memory cells internally.

fast
also erases hidden areas
bypasses wear leveling

Linux

hdparm --user-master u --security-set-pass PASS /dev/sdX
hdparm --security-erase PASS /dev/sdX

NVMe:

nvme format /dev/nvme0n1

Windows / macOS

The easiest way is usually through vendor tools:

Samsung Magician
Crucial Storage Executive
WD Dashboard
Intel SSD Toolbox
Kingston SSD Manager

Alternatives to destruction (SSD)

SSDs are expensive, so physical destruction is often not desirable.

use Secure Erase
full-disk encryption (BitLocker, LUKS, FileVault)
then delete the key → data becomes unusable

USB drives and SD cards

They behave like SSDs. Overwriting is only reliable to a limited degree.

Linux

sudo dd if=/dev/zero of=/dev/sdX bs=1M status=progress

Windows

diskpart
select disk X
clean all

macOS

diskutil eraseDisk free none /dev/diskX

When physical destruction makes sense

defective storage media
very sensitive data
no trust in erasure

Methods

HDD: drill through the platters
SSD: destroy NAND chips
professional: shredding

Business: professional data erasure

In business environments, erase certificates are often mandatory.

Blancco
Certus Software
certified disposal providers

These provide traceable erasure reports and are GDPR-compliant.

Common mistakes

only formatting
handling SSDs incorrectly
choosing the wrong device

If having full control over your data matters to you, it’s worth taking a look at tools like Joplin, which allow you to manage your data entirely on your own.

Data security doesn’t end with deletion. With Catarix IT, I help find secure and sustainable solutions.

Conclusion

Secure data erasure is not a question of one tool, but of the right method. If you distinguish between HDDs and SSDs, you can protect data reliably.