So You Want to Destroy a Hard Drive

Category: Hard-Drives

A concerned reader asks: 'I am getting rid of an old computer, and I want to make sure NONE of the data on the hard drive can be be accessed. (Don't ask me why) What is the best way to destroy a hard drive and ALL the data on it?' There are plenty of options, read on for my advice...

Hard Drive Destruction

It sounds like a low-budget movie made for geeks, but the topic is serious. When you plan to get rid of an old hard drive, you really should render it totally inoperable. Tossing a hard drive in the trash, even after reformatting it, can expose your private or sensitive data to a clever person, and make you easy prey for identity thieves.

In most cases, using special software designed to completely erase the data on a hard drive is sufficient. See my related article Securely Erase a Hard Drive for some tips on doing that. But no matter how many times you reformat, repartition, or overwrite every sector on a hard drive, it may still be possible to recover some data from it - if the drive's magnetic platters will spin. So to destroy a hard drive with complete certainty you need to destroy the platters. There are right ways and downright dangerous ways to destroy a hard drive.

Years ago I read a story about a paranoid man who had rigged up a system to destroy his hard drive in the event that the "men with dark sunglasses" came knocking on his door. He had a kill switch that would turn on a powerful magnet, which he assumed would wipe the drive clean. But subjecting a hard drive to a strong magnetic field will not do the trick; that doesn't bend the platters out of shape, it just obscures the data. Nor does microwaving a hard drive do any good. (Microwaving does work on plastic CDs and DVDs by melting the tiny pits that encode data.)

How to Destroy a Hard Drive

Note that "death by fire" is a dangerous method; there are many toxic chemicals in hard drives and optical disks that you don't want to inhale.

Brute Force and Other Methods

Keep things simple whenever possible. Your goal is to render the hard drive's platters unreadable. Primitive brute force is the obvious and richly satisfying solution. Drive sheet metal screws through the hard drive. Drill holes through it. Both of these techniques will make it impossible for a read/write head to hover over the platters without crashing. A sledgehammer applied vigorously until the hard drive is no longer flat also works. Of course all of these methods require some safety equipment and adult supervision.

But amazingly, with the right forensic tools, data can still be recovered from the unpierced and unbent portions of platters. An even more complete technique for destroying a hard drive is to disassemble it; remove the platters, and sand or grind their surfaces with power tools. (I recently bought an angle grinder from Harbor Freight for $15 and now it's my favorite tool.)

Are there computer viruses that can physically damage a hard drive? Is it even possible, or is this an urban legend? See my article Can a Virus Really Destroy a Hard Drive? to learn the truth...

Acid can destroy the surface of platters, too, but you run the risk of burning yourself and inhaling damaging fumes. Muriatic acid, sold at home improvement stores, is strong enough to do the job on a hard drive. Again, safety first.

You may have to buy or borrow a set of Torx wrenches to remove the special screws used to seal a hard drive's case. Before spending money, try prying the case off with a large, flat-head screwdriver or chisel. Encasing a hard drive in cement, plaster of Paris, or clear acrylic is another way to ensure its platters are inoperable. A clear acrylic tomb also makes an interesting paperweight! Explosives are sometimes used to destroy a hard drive. YouTube can provide examples of such techniques, but it's safe to assume they are prohibited by local and federal laws.

The safest way to destroy a hard drive is to send it to a facility like Ameri-Shred that has heavy-duty metal shredding machines. Do a Google search for "hard drive shredding" and you'll find quite a few companies that will do the job. You may find that watching this video of a hard drive shredder almost as satisfying as doing it yourself.

It's tempting to recycle computers or hard drives by donating them to charities, schools, friends, and other people in need. But remember that a hard drive may contain data you've completely forgotten about yet would be horrified to have someone else discover. It's unlikely that your neighbor or a middle school student has the savvy to recover data from a thoroughly "wiped" hard drive. But you don't know where that drive will end up; it might find its way to unfriendly hands somehow.

Do you have something to say about destroying a hard drive? Post your comment or question below...

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This article was posted by on 10 Mar 2020

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Most recent comments on "So You Want to Destroy a Hard Drive"

(See all 36 comments for this article.)

Posted by:

10 Mar 2020

Did anybody else spend ages watching videos of shredders?

There is something hypnotic about all that relentless, implacable power steadily and inexorably reducing our complex artifacts to small, almost uniform bits.

I'd like to watch one in reverse!

Posted by:

10 Mar 2020

I open the drive and remove the platters. Next I use the magnets from a destroyed hard drive to rub over the surface of both sides Once this is done I rub the platters on a concrete surface to scratch them thoroughly. Next I take the platters and bend them over twice and smash them mostly flat into a quarter pie shape. Now I wait and toss the remains into the garbage truck and never let them sit in a garbage can. Let some one go into several tons of garbage to get that out?

Posted by:

11 Mar 2020

I have been drilling a half dozen 1/4 inch holes with my drill press and pounding them with a 2# hammer. Satisfying.
I think now I will drill a few more.

Posted by:

11 Mar 2020

Has any one tried to soak the hard drive in a very, very, very salt water for days?? Will this method work? Your comments please.

Posted by:

11 Mar 2020

Bleachbit. If it's good enough for Hillary, it's good enough for me!

Posted by:

11 Mar 2020

I remove the hard drives from the old computer, retrieve the rare earth magnets (I don't know what I'm going to do with them), and then use a shop grinder to shred the hard drive into pieces, chips and dust and then dump half of it into the trash, wait a couple of weeks and then dump the other half.

Posted by:

11 Mar 2020

Hard drives make very good target practice material. A half dozen or so shots from an AR, AK, or 308 will disable a hard drive.

Posted by:

11 Mar 2020

In the early 90's a couple of my colleagues went on a data recovery course including 3.5" floppies.

Part of the course was to try to wreck floppies with rules including , you had to have all the bits and you couldn't leave the room. The last rule was introduced when the course was held at a military research base. The attendees took the disk out of the room and returned with a smouldering lump in a container held on the end of long tongs held in heavy gloves.

Posted by:

11 Mar 2020

I think good target practice is maybe the bust way.

Posted by:

11 Mar 2020

Frankly, I find all this talk of physically destroying hard drives, which are amongst the most refined pieces of technology we can own, unnecassarily brutal!
Modern drives have tracks which are a tiny fraction of a micron across, so the days when forensic experts could recover trails of data left at side of the tracks are long gone.
Just over-writing all the data once with a suitable utility program should be quite enough to stop anyone (and in any case, who wants to?) from obtaining any files: using a multiple over-write option is also possible for the ultra-careful...

Posted by:

11 Mar 2020

What? No mention of opening the case and using a common blow torch to heat the platter until it loses its magnetic coherence? I found it remarkably quick and less dangerous than beating with a hammer. Though I could see where shooting a platter for target practice could be fun. :)

Posted by:

11 Mar 2020

Bach in the 70's, while in the military, I worked in a large computer facility located in a foreign (semi-hostile) country. We had very large disk drives (the size of a washing machine). Each drive had a thermite grenade in a small container sitting on top. In the event of a hostile takeover we were to pull the pins and run. We all looked forward to the time when we'd get to do this. Unfortunately peace broke out and we never got to witness the expected carnage.

Posted by:

12 Mar 2020

Wow! What are you storing on your drives that require that level of destruction?
If you a really that concerned break out the platters and randomly dispose of them, after mutilating if you must, but I'm guessing most of your data is already up in the cloud and therefore well out of your reach. I do like the thermite solution though :)

Posted by:

12 Mar 2020

I've only destroyed 2 HDDs, but I have a friend who's a welder.
BTW: To destroy an HDD with heat, it needs to get to 1100 degrees centigrade, and then cooled to below 900 degrees centigrade - the cobalt will oxidize to Co3O4 (cobalt tetraoxide), then when cooled, it loses three oxygen atoms and 2 cobalt atoms and becomes CoO (cobalt oxide) which is unreadable by any known method (magnetic, laser, electronic, re-imaging, etc.).

Posted by:

David Baker
14 Mar 2020

Bob, I think your shredding idea is the safest and most eco way destroy a hard drive.

Posted by:

19 Mar 2020

I am sure that using at most two "military grade" wiping utilities would render any hard drive completely unreadable. There must be something terrible that would make a person wish to destroy HDD.
Some time ago Bob listed a utility that would access a HDD's native drive wiping function that is normally not accessible to the user for data safety reasons. This and one other good wiping agent, set to multiple passes would defeat even the most arduous attempts at data recovery.
If you wish to then destroy the disks, the above advice to scrape or sand the shiny platters could finish them off. And also as mentioned above, the magnets inside are super strong and very useful around the house.

Posted by:

19 Mar 2020

I forgot to mention the principle of obscurity by anonymity. If the HDD is of useful capacity, rather than destroying it just wipe it thoroughly as I detailed in my message above, then copy some benign files like landscapes or classical music on it and drop off at a thrift store. I hate to see waste.

Posted by:

27 Mar 2020

I was really hoping that someone else would contribute, but the comments have stopped, so here is the info on "Secure Erase" from Bob himself:

...NIST (the U.S. National Institute of Standards and Technology) rates it as good as degaussing a hard drive - that is, using a powerful magnet to completely scramble the bits stored on a drive. So why haven’t we been using “Secure Erase” for all these years?

...Most BIOS developers disable the “Secure Erase” feature because they think consumers won’t use it wisely. Indeed, “SE,” as it’s called, is a “nuclear option.” It wipes data, and no amount of panicked, tearful phone calls to tech support or data recovery specialists will get it back. It even wipes data stored in bad disk blocks, something other disk-wiping utilities can’t do. When Secure Erase finishes its job, your hard drive will be squeaky clean

Unlock the Power

A freeware utility called HDDErase 4.0 unlocks the power of the Secure Erase feature in nearly every standard magnetic hard drive built since 2001. You can download it from the UC-San Diego’s Center for Memory and Recording Research, but note that no tech support is available and you use it at your own risk. Because it runs from a bootable disk, HDDErase can erase any operating system, using the drive's own built-in sanitizer. Tim Fisher’s review of HDDErase provides a little more insight into this powerful command-line utility.

I've read in various places that HDDErase will work on SSDs (solid state drives) in addition to traditional spinning magnetic hard drives. But the documentation for the program does not mention SSDs at all. However, this article on the Kingston Technology website seems authoritative, and does specifically mention using HDDErase with SSDs.

There is one important caveat, though, according to Kingston. HDDErase can only be run on hard drives that are directly attached to a SATA or IDE port, and not through a USB bridge or enclosure. Put more simply, HDDErase will ONLY work on internal drive, and WILL NOT work on external hard drives.

Posted by:

02 Apr 2020

I like most of the ways to kill a harddrive. I like the good old way of a very large tool to make them small, like pancake.

Posted by:

13 Jul 2021

When I need to destroy a hard drive i dismantle it and I take the aluminum discs; whose melting temperature is 1,220 degrees Fahrenheit. I put them into my mini barbecue grill to smelt them using THE BEST Hardwood charcoal that burns at 1,100 degrees Fahrenheit. Putting a small fan on high speed 1 foot away next to the grill raises the charcoals temperature to 2,000 degrees which will melt the aluminum discs into molten blob within 1 hour.
When the aluminum cooled enough to be handled i drilled holes into the blob and made it into a necklace. Data restoration is impossible using this method of destroying a hard drive.

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