What is the best way to safely and completely erase all data from old laptops?

NotSpez@lemm.ee to No Stupid Questions@lemmy.world – 56 points –

I have a couple of old laptops lying around and want to throw them away, but have been cautious to do so because of privacy concerns of data still on the hard drives. What is the best way to wipe them? Or should I take them out and physically destroy them?

They are running windows vista and 10 I think.

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I like to take the hard drive(s) out and either drill holes in them or beat them to pieces with a big hammer.

Dear old Dad worked in IT, and he had a clearly marked "hard drive eraser". It was a 20 pound sledgehammer.

Doesn't that still leave most of the data on it? You don't even bother erasing the drive first?

It takes far more work to recover data off of smashed platters than Joe the average users data is worth. There's very few ways to make that data completely nonrecoverable. Even zeroing the drive isn't 100% safe from someone with the right resources and knowhow. Just smashing the platters makes data recovery enough of a pain that it's almost never worth it.

Data on a HDD that’s been overwritten with zeros or random data is unrecoverable with all known current technology.

In theory it might be possible to recover something with some future tech that hasn’t been invented yet, which is why the DOD standard requires erasing with multiple passes, but there isn’t currently a (publicly known) way of doing it.

SSDs are a bit tricky because of wear levelling, but usually two full overwrites of a SSD makes it just as unrecoverable.

I don't see how much data can be recovered from broken, bent pieces. If you're really concerned, you can use a torch to raise a magnetic platter until it glows, this raises it above it's curie temperature so all the magnetic particles stop being magnetic.

The easiest options in order of effectiveness, and how to bypass them:

  1. Do nothing.
  2. Reset Windows or erase all files you don't want to be found. To recover from this you need a specialised piece of software that will recover the files, but not the names or locations, so while the actual data is easily recoverable, the person would need to sieve through most files you've had in your PC since forever with no order.
  3. Zero the disk, my way to do this would be to boot a Linux USB and run for example dd if=/dev/zero of=/dev/sda, this will delete EVERYTHING on that disk, including windows, partition table and the bootloader. The way to recover from this involves specific hardware and a sterile lab, unless the authorities are investigating you it's very unlikely someone will recover from this.
  4. Multiple passes with zeroes and random data, the way I would do this is the same as above but use /dev/urandom for the if parameter, run it multiple times, then run once with zeroes. Theoretically it could be possible for the same lab as before to recover some data if the machine ran out of entropy and didn't wrote actual random data, and someone could predict the random data and compensate for it on the residual magnetic field, but it's highly unlikely. Almost no one would be able to recover this, and if someone can they will charge A LOT.
  5. Physical destruction, e.g. drill a hole or smash the disk for an HDD, break the chips for an SSD.

All of that being said, why throw it away? Why not sell it or use it to self-host something cool like a media centre or a steam machine if the laptop is good enough.

Laughing at all the Hollywood shit in this thread. A single pass erase (or ATA Secure Erase, if they are SSDs that support the command) is more than enough. Nobody is going to waste time and money recovering data of unknown provenance from a landfill.

HDDs also support ATA Secure Erase, although it will take a few hours rather than the few minutes it would wirh an SSD.

Yes, unless they are OPAL, in which case it's done the same way as SSDs: throw away the key.

Hammer, then marinate for atleast 30 mins in soya sauce, onion, garlic, herbs, then bbq, eat and poop in 3 different bathrooms across the city. Pro tip, sprinkle with olive oil each side while on the grill.

  1. There are companies you can pay to physically shred your disk drives. You have to be able to trust them of course for this to work.

  2. Or if you want to DIY, you can drill or smash your drives. Just wear eye protection, etc. Making the drives inoperative like this is the only thing I'd trust, but you can also software-wipe them first.

Great tip on the eye protection! Metal splinters are a nightmare for any future MRI’s one might need.

Yeah, we have a company that does e-cycling events every month. I usually go there once every 3-4 months with my various electronic goods,

It costs (currently) $5 a drive, but they shred the drives on site, AND bring you to where they shred them to watch to ensure they get shredded.

I personally remove the hard drives from any enclosure/laptop/desktop after wiping as a force of habit, as they charge an additional fee to pull the drives out for you.

If you're in the states, you can usually look on your county government's website for when e-cycling events occur. The ones where they're quarterly at a centralized location such as a mall parking lot, or a park parking lot, you're likely going to have to rely on them shredding elsewhere and you cannot be certain they're destroyed. However, the places that do the e-cycling at their own center, you'll likely be able to do the above and watch the drives be shredded.

As others have said, destroying with a drill or the like is more than adequate, however the MOOP from it isn't great for the environment, animals, or your feet if you happen to do the destruction inside / outside your home.

If you just do the simple one-pass zero-ing out, suggested a few times here, the data is only recoverable in theory. There are labs that do it, but they charge thousands of USD for a drive and giving limited results.

Unless you are being actively targeted by deep pockets, that's plenty good enough.

And if you do a couple passes (might take a bit but who cares if youre throwing the whole thing out) then in theory even the nsa can't get in it

It depends how badly you need that data to never see the light of day again. Most likely, you'll be fine to erase the drives with secure erase options (where it writes 0 and then 1 to the whole drive, and back and forth a few times depending on settings), but if you really really need to 100% guarantee there's absolutely no chance of recovery, then you'll need to destroy the drives physically

There is nothing extremely sensitive on there, but the more time I spend on lemmy (as a bit of a tech noob) the more I care about privacy

In that case, secure wipe should be more than enough

also, if you're getting rid of them, there might be a charity you can donate them to rather than just tossing them. Idk any off the top of my head, but it seems worth looking into

If you live near an active volcano, dumping them directly into the core should be pretty effective

If Gollum doesn’t try to stop me…

Geez at the answers in the thread. Boot off a USB drive with Linux, right click the HD, and simply format the drive. Not a quick format, you may have to unselect that. You'll know because a quick format will take seconds, a full format will take an hour (depending on the size of course).

Then donate the laptops. Donation place should be able to install Linux. Most people don't need much laptop.

Hmm, what does that full format do? Write zeros over everything?

Personally, I would run shred on the root filesystem. It's a tool specifically intended for properly deleting data (overwrites it with random data multiple times).

Even writing 0's takes hours per TB sometimes. Guess it depends on how much time you have

It took maybe 10 minutes or so for a 256 GB hard drive for me, if I remember correctly.

That was an SSD, though, so yeah, mileage would definitely vary on an HDD.

You've said you're intending to throw these laptops away, so physical destruction is quickest and simplest.

But, if you're intending to sell or give these away for someone else to use, zeroing each sector is probably 'good enough' for your purpose (as someone else has always said).

If you really want to make it harder, you can use something like the Boot and Nuke bootable Linux disk for the job, as it also has the option of multiple passes, using zeroing and/or binary random shit for each sector. Just grab the free for personal use version.

Turn on laptop

Hold magnet over where the hdd is

Listen to laptop scream in pain

Stop 🛑... Hammer time 🔨🕓🖥️

Or 🧲 or 🪓

💀

I work at an electronics recycling facility and all laptops that are recycled are completely sanitized and properly disposed of as e-waste. Look around for a local recycling center and check for an R-2 certification, if they have one they will take out any identifiers and do passes on drives via a sanitization device to ensure that the whole thing is completely devoid of all data.

This is the correct answer. Give it a format just to be sure then donate it to a recycling center.

Smuggle the laptops into the cargo bay of Elon's next Starship launch.

Since no one mentioned it: VCR tape eraser.

Basically just an electromagnet that oscillates because it's running directly from AC current.

With an extension cord you could erase all the hard drives in a computer lab just waving the eraser vaguely where the drives are.

Physical destruction is better though.

Unfortunately the degausing trick doesn't work that well with newer higher capacity harddrives. As capacity increases they actually need to be less sensitive to magnetic fields to prevent multiple bits flipping when the drive head tries to write data. With modern multiterabyte harddrives you're going to have a hard time reliably wiping the platters with anything short of an MRI magnetic field. That's not to say smaller magnetic fields like degausing coils can't be damaging; they will just take a long time to destroy enough of the data to prevent recovery. You're actually more likely to break the drive heads with a degausing coil than you are to wipe the platters.

If they are Windows and have Bitlocker encrypt the whole drive and throw away the key. If not get Veracrypt for free and encrypt the entire drive. Once the drive is fully encrypted and has no backup key you can just trash it. If this was commercial use I would then send it to a third party to be certified destroyed.

'zeroing' every sector is probably 'good enough' for mechanical hard drives.

if the laptops are functional:

boot a target laptop to a windows install disk or usb. at the first prompt, hit SHIFT-F10 to open a command window.

diskpart

list disk

select disk 0
(laptop internal drive should be disk 0)

clean all
(this will take time. on an older laptop, up to maybe an hour per 250gb of hdd capacity.)

exit

power off.

if they're NOT functional laptops:

remove the hdd (search the make and model at yt for guides), connect to another pc (via usb adapter) or internal inside a dt. boot to that system's normal windows, run diskpart from an admin command prompt.. do the same as above but note that in this case: IT WON'T BE DISK 0 -- be sure to 'select' the correct disk

if one of them happens to be an ssd. instead of wiping it (this method isn't for ssd, btw), get an enclosure for it (as little as $8-10) and use it as an external disk.

The only way to completely erase all data beyond recovery is to destroy the disk e.g. snap in half and move a powerful magnet above it.

Use vericrypt to encrypt the drive with a long random password and immediately forget said password

Just turn on disk encryption.

Cracking encryption gets easier over time. This is a timebomb.

True, but if all the data was encrypted, then the drive formatted it would require physically dismantling an HDD in a clean room to recover data, for SSDs the wear leveling makes it hard to fully erase anything, but again, after encrypting and formatting the cost of the tools needed to get the data back are well above the potential benefit (i.e. there are easier ways to get people's personal info)

I don't understand why filling the drive isn't enough to overcome wear leveling.

It absolutely is. The thing that isn't enough is doing a full disk TRIM, but I haven't seen that recommended. A single pass of dd if=/dev/zero is plenty adequate.

Depends on the type of drives and your needs.

If the drive is big enough to be used as storage/back, get it out and in its own USB enclosure.

If the drive is either too small or you have too may already then :

  • SSD : smash it to pieces with a hammer
  • HDD : if you're sure it's not an hybrid (in which case the SSD process applies) then you can just fill it with garbage or use whatever "erasing" software out there. I would go for an open-source one.

A muktipass erase is the right choice.

To do this, you will need to boot the laptops from something other than the internal hard drive. I would download a Linux distro and put it on a usb drive. Boot them from the USB then wipe the internal drives using a secure option.

HDDs have some strong magnets inside that I like to salvage. Once I have those, I put the shiny plates into a ziplock bag and smash them.

The only way to be 100% sure is to replace any and all hard drives and destroy the old ones.

Edit: some reason I thought you were selling them not tossing them, there's no need to replace the hard drives in that case, just remove them and destroy them