Special Feature
Part of a ZDNet Special Feature: 2010s: The Decade in Review
Our editors pick the products and services we write about. When you buy through our links, ZDNet may earn a commission.

How to securely erase hard drives (HDDs) and solid state drives (SSDs)

Got a pile of old drives that you need to wipe before sending them to Silicon Heaven? Or do you want to wipe a drive in a computer that you are selling or giving away? Here are some tips and tricks to help you get the job done.

Hard drive destruction

Got a pile of old drives that you need to wipe before sending them to Silicon Heaven? Or do you want to wipe a drive in a computer that you are selling or giving away? Here are some tips and tricks to help you get the job done.

Security

Cyber security 101: Protect your privacy from hackers, spies, and the government

Simple steps can make the difference between losing your online accounts or maintaining what is now a precious commodity: Your privacy.

Read More

Since hard drives (HDDs) and solid-state drives (SSDs) need different handling, so I'm going to cover them separately here.

HDDs

There are three approaches you can take to securely wiping hard drives.

Software

The cheapest way to tackle a pile of hard drives is to wipe them with a software eraser. I will warn you though: it's not quick, and it won't work on defective disks.

My tool of choice for wiping drives is Darik's Boot And Nuke. It's free and does an excellent job of wiping drives clean.

2014-02-0723-27-06.jpg

To use it, you'll need to create a wipe CD or DVD, then hook up the drives you want to wipe to a PC, and run the software. Be careful not to inadvertently wipe a drive containing data you need because that will make your life suck. I suggest using a spare PC or, failing that, disconnecting all the data drives from the system you use, just in case. You can do this since you'll be booting up off the Boot And Nuke disc and not the internal drive.

I recommend that you read and thoroughly familiarize yourself with the documentation for this software because if you take your eye off the ball and wipe the wrong drive, your data is gone.

Hardware

If you don't feel like taking the software approach, another method you can take is to employ a bespoke hardware tool to do the job. At this point, though, things start to get a little expensive, but it is faster and does mean that you don't have to dedicate a PC to the wiping operation.

The tool I use is Wiebetech's Drive eRazer Ultra. It's a fast, reliable, standalone solution to wiping hard drives and deleting everything. You hook up the drive to it, tap a few buttons, and Drive eRazer Ultra takes care of the rest.

2014-02-0723-24-49.jpg

I've used this tool to wipe dozens of drives with great success. It's an expensive solution for sure -- the eRazer Ultra starts at $250 -- but if you have a lot of drives to wipe, it's well worth it.

If you have a lot of drives to erase, then you might want to go for a tool that can erase multiple drives simultaneously, such as the StarTech four-bay drive eraser.

The StarTech four-bay drive eraser is packed with the following features:

  • Secure, standalone drive erasing for up to four 2.5-inch and 3.5-inch SATA SSD/HDD drives
  • Nine erase modes including: Quick and Secure Erase, Single Pass Overwrite, and Multi-pass Overwrites -- meets DoD (5220.22-M) standards
  • Support for Secure Erase and Enhanced Secure Erase for SSDs
  • Easy operation with LCD and push-button navigation
  • The built-in nine-pin serial port enables you to print erase logs using a receipt printer
  • Supports SATA I and II (up to 3Gbps)
  • Also supports 2.5-inch and 3.5-inch IDE hard drives, mSATA drives, and SATA M.2 drives using a compatible StarTech.com adapter
  • TAA compliant
  • Plug-and-play installation

Out of the box, the four-bay unit is capable of dealing with 2.5-inch and 3.5-inch SATA drives (both SSDs and HDDs) and the hard drive eraser also works with 2.5-inch and 3.5-inch IDE hard drives, mSATA drives, and SATA M.2 drives using a compatible StarTech.com adapter.

The hard drive eraser is easy-to-use, thanks to its convenient menu navigation system, with push-button operation and a built-in LCD that clearly identifies the erase modes and task status. You can also connect the eraser to a computer to quickly access the drive that's attached to port-1 on the eraser.

To ensure your records are complete for auditing, the hard drive eraser features a nine-pin serial port that can connect to a serial printer to provide on-demand erase logs.

The hands-on methods

OK, what do you do if you want to wipe drives that have died or become defective in some way with data still on them that now cannot be wiped? You could take a chance that since the drive is dead, the data is gone, but you got to plan on the drive falling into the hands of someone cleverer than you (or someone who has more time, patience, and resources).

Here's where the hands-on methods come into play. These methods also work great if you just want to destroy drives before you take them to the recycling plant.

I have two methods. A surgical method, and a more medieval method.

For the surgical method you will need:

  • A drill and HSS drill bit (I use about 1/4-inch/6mm) -- you see where I'm going with this
  • Thick gloves -- shards of metal will shred you
  • Eye protection -- we're destroying drives here, not eyes
  • A vice or clamp -- stops the drill bit from getting caught in the drive and turning it into a wildly spinning and flailing object

I then go about drilling three holes as shown below. If you want speed and only want to drill a single hole, pick the spot with the X. For a more complete job, hit the green stars, too. See the video above for a step-be-step guide. 

You can also optionally put a couple of holes in the circuit board on the other side for good measure.

2014-02-0723-21-00.jpg

Then there more brutal method. For this, you will need:

  • A hammer -- I use my trusty 32oz "fine adjustment" hammer
  • A thick nail -- a 6-inch nail will do fine
  • Thick gloves -- because you're going to be hammering that nail through the drive using the hammer, and hammers seem to be inexplicably attracted to thumbs
  • A block of wood -- so you don't nail the drive to your floor (it's preferable to do this outside if you can)
  • Eye protection -- you've only got a maximum of two to start with, so it's silly to take chances!

Now, you apply brute force. Ideally, you want to put a nail through the platters of the drive, going all the way through (it's actually not as hard as it sounds). Again, aim for the spot marked by the red X, and optionally the green stars for a more complete job.

This is a very effective method of destroying drives, and it's also a lot of fun, not to mention a great way to relieve stress!

SSDs

With solid-state drives, things can get very complicated, and I could write reams about TRIM commands and garbage collection, and so on. The problem is things get convoluted, which is when mistakes happen and your precious baby pictures or work project gets deleted. With that in mind, I'm going to keep things simple.

Erase using manufacturer utilities

One way to erase SSDs is to use the manufacturer's utilities. Here are some links to get you started.

If you have a drive from a different source, go check out their website.

Encrypt the whole drive

One of the easiest ways is to encrypt the entire drive with a complex passphrase. On Windows, you can use something like VeraCrypt. On Mac, you can use the built-in FileVault utility, and you're done. No passphrase, no data.

You can then format the drive, from which point it should be sterile and ready to accept a reload of the data.

PARTED Magic

Another way to do this is to use a software tool called PARTED Magic. This supports both HDDs and SSDs.

While PARTED Magic is not free (price starts at a reasonable $11), it is a very effective tool, and one of the best I've used for wiping SSDs.

The hands-on method

If the drive is dead, or you just want to get rid of it in a hurry and don't want a functioning drive at the end of it, then you can take a hammer to the SSD or flash drive.

One thing to bear in mind is that the data in SSDs is held on small flash storage chips rather than large platters, and to securely erase the data, you need to smash the chips. Usually this means taking the cover off the drive before you start swinging.

If you're not sure which are the flash storage chips, just drive a nail through all the large chips to be on the safe side.