Securely Wipe a Hard Drive using Built-in Windows Tools

I have been doing a bit of cleaning house lately and have no less than 7 old hard drives sitting in my office. So I had a few questions to answer. First… are they usable? Second, if they aren’t, how can I securely dispose of them?

To answer these two questions I am using two pieces of software, a sharpie marker, and a handy, albeit slow, USB 2.0 –> SATA hard drive cradle. My recommendation for what follows is that you forego the cradle and directly attach your drives to your motherboard if you have the ports and technical capability to do so.

Answer the first question was easy enough, using a free tool called “Crystal Disk Info,” I was able to quickly ascertain the S.M.A.R.T. status of all of my drives. If you don’t know what S.M.A.R.T. is, just Google it… Anything that was “bad” or in a “warning” state was going to be wiped and tossed (or shredded if you are extra paranoid like me). You can get crystal disk info (freeware) from here: http://crystalmark.info/download/index-e.html

I recommend the “portable” standard edition as it comes sans ads and any additional junkware.

Identify Messed Up Drives:
Attach each drive, run Crystal Disk Info, and then use your sharpie marker to write, good, bad, or warning on each one.

Wipe Drives:
Okay, next you need to actually “wipe” the drive. Someone at this point might ask why simply deleting files or formatting the drive won’t work. I am not going to get into a lot of detail here but basically a hard drive is just a collection of 0’s and 1’s – the unique combination of which = your files/data. A “file system” on the drive is exactly that, a system for keeping track of files. When you delete a file, the data isn’t actually gone, rather, the sectors on the hard drive that hold the data are marked as “available” so that they can be written over when you need to use that space. So deleted files could be recovered with time and the right software if those sectors haven’t been re-written with something else. So, how do we “wipe” the drive? Very simply, we write zeroes to every sector of the disk. If we are paranoid, or have regulatory compliance in view, we do it several times. I am assuming you aren’t that paranoid and this is for personal use and have no legal requirements in view…

So, what do we use to “zero out” our disk? Windows ships with a simple command-line tool that can be used to do just this… diskpart… First, attach your hard drive to your system (via a USB enclosure, or directly, either will work). Then…

1. Open up an elevated command prompt by clicking the start menu button, typing “cmd” and then right-clicking on the cmd.exe icon that shows up and hitting “run as administrator” from the context menu.

2. In the command prompt, type “diskpart” without the quotes.

3. The diskpart command prompt will open and will show like this:

4. Type “list disk” and hit “enter”, you should get something like this:

You can see all of the hard drives attached to your PC. You need to identify the one you want to wipe and make absolutely certain you have selected the correct one because we are about ready to get rid of all of the data on it more or less permanently. I have found that the GUI tools found at: control panel –> system and security –> Administrative Tools –> “Create and Format hard disk partitions” is useful for identifying which disk I want to select. For this example, lets assume I want to wipe “Disk 3” from the list above. From the diskpart command line I will type “select disk 3” and hit “enter”. It should look something like this:

Finally, this is the last command that will zero out the drive, type “clean all” and hit “enter”

The “clean all” command tells diskpart to write zeros to every last sector of the hard drive, effectively wiping it clean. You will see a little blinking cursor while it runs, and unfortunately it will not give you any kind of indication of how far along it is or how long it will take. A general rule is about 30 GB/hr on a direct attached drive (not USB 2.0) so a 300 GB drive could take 10 hours or so. So expect it to take all day or longer for very large drives. If you are doing this via a USB 2.0 connection it will most likely take significantly longer (5x – 10x as long depending on the type of drive) so a direct connection is preferable when possible.

After you have done this, I still recommend using a service like Iron Mountain (drop off bins at places like Staples) to securely, physically, shred the drive.

NOTE: If you have time and want an even more secure “wipe” of your drive, look into an application like DBAN (Derrick’s Boot and Nuke). Diskpart Clean All, based on all my reading, pretty much is the same as a single-pass of DBAN, which is sufficient for me. But I realize some folks might want something even more thorough for peace of mind…