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What products or best practices are there for completely removing all data from a hard drive? Is there a software based solution that is better than microwaving or physically disassembling the drive? What about with solid-state (flash) drives?


asked May 02 '11 at 18:04

oliver's gravatar image


For non-SSDs I would use a tool like TrueCrypt full-disk encryption. You encrypt the entire disk, including all system partitions, and then change the key to a very long random string. Then format the drive.

If you even put sensitive data on a non-encrypted SSD then an good way to physically decommission the drive is to heat it with a propane torch until the PCB catches fire. At that point the magnetic domains aren't magnetic anymore.

3 years, 8 months ago
willyyam's gravatar image willyyam

12next page »

DBAN http://www.dban.org/. Free, and very thorough. Wikipedia link: http://en.wikipedia.org/wiki/DBAN


answered May 23 '11 at 17:09

Derek%20Murawsky's gravatar image

Derek Murawsky

edited May 23 '11 at 17:36

Due to the internal wear-leveling algorithm used by SSDs there is no guarantee that DBAN or any other wiper software will wipe all of the data - only the reported data. SSDs contain (internally) a certain percentage more space than they report in order to extend the life of the drive. The wear-leveling algorithm could have placed data in one location that is ignored because it has been written more often than the others. When you write all 0's or random garbage to the total reported drive space you can't be certain that 100% of the total actual space in the SSD has been wiped.

3 years, 8 months ago
sfriederichs's gravatar image sfriederichs

@sfriedrichs, does that mean for Macs using SSDs that using a 7 or 35 pass 0 fill through Disk Utility is the best bet?

3 years, 8 months ago
oliver's gravatar image oliver

No, recent work out of UCSD suggests that there is no way to ensure that SSD data is actually erased from an SSD. The access to the underlying blocks and the efficacy of the delete protocols vary widely. If you are concerned about data ever coming off the drive you cannot reuse SSDs.

3 years, 8 months ago
willyyam's gravatar image willyyam

@sfriedrichs: True, SSDs are particularly difficult in this regard. However this is still the best bet around aside from slag-ing the drive (melting it). The reason zero writing isn't acceptable with magnetic media is that it is possible to determine the previous state of the bit with an electron microscope. In fact, this is possible for several passes of data writing. Even if you flop it 0-1-0-1 a few times. The whole point of random data writing is to confuse a would-be forensic analyst by giving them millions of possible combinations to sift through.

3 years, 8 months ago
Derek%20Murawsky's gravatar image Derek Murawsky

One thing most folks don't consider, though, is are you really a target for that kind of search? It takes a lot of time and money to go through a drive like that. Most likely your collection of pictures or documents will not warrant such a search. I stand by my recommendation of DBAN for 95% of what's out there, even SSDs. Here is a tool for SDD secure erasure: http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=18455 If you really want to be sure, degauss and slag it. Just be careful, doing that is dangerous (and fun).

3 years, 8 months ago
Derek%20Murawsky's gravatar image Derek Murawsky

Maybe Ontrack Eraser can do the trick. My dad use it in his work, collecting computers from companies who wants to donate there old computers to Africa. They use the software because the company behind the software provides a certificate that stats that all data have been completely destroyed. They even say that it is better to use this software then to physically destroy the hard drive, because the drive can be reconstructed and analyzed.. But other then that, I don't not nothing about it.


answered May 23 '11 at 17:15

Anders%20Johansen's gravatar image

Anders Johansen

edited May 24 '11 at 00:30

Connect the drive to any Mac and use Disk Utility to do a single, 7 or 35 pass 0 fill of your drive. Attempting to restore the drive will just recover zeroes.


answered May 23 '11 at 21:29

Dave%20Dash's gravatar image

Dave Dash

a large hammer


answered May 23 '11 at 22:53

Chloe501's gravatar image


The 7/35 pass options are called DoD standard but those were based on old paper about recovering data from MFM and RLL drives. Modern drives are completely different and can't be recovered as simply.

A single pass of zeros will be sufficient for spinning drives. Note that modern drives will automatically relocate bad sectors as it finds them and the zero pass won't write to those sectors, old data may remain on those sectors even with the 7/35 pass options as the drive skips over them anyway.

If you just want to keep people from using computer based recovery tools from getting data off your drive then a single zero pass will suffice. If you want to prevent more, then slag it, there are no ways to guarantee full erasure of absolutely all data.


answered May 31 '11 at 10:01

kvanh's gravatar image


Go with the low-tech approach and proven method....just take a hammer to it and save yourself the uncertainty that the software worked.


answered Jun 01 '11 at 18:01

hobbes's gravatar image


The only product I've found so far that can delete free space from SSD is O&O SafeErase 5:



answered Jun 07 '11 at 18:27

Stinklington's gravatar image


methylethylkeytone bath or and not, not simultaneously_, fire.


answered Jun 07 '11 at 20:34

Chloe501's gravatar image


Visit this link to get Best solution to your problems http://www.easyrecovery.co.uk


answered Dec 30 '13 at 23:04

anthonyohare's gravatar image


edited Dec 30 '13 at 23:05

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Asked: May 02 '11 at 18:04

Seen: 13,250 times

Last updated: Jul 01 '14 at 22:40

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