How to securely erase your hard drive before disposing it
Visit any modern home, chances are there are at least several computers which are outdated and not used anymore, it’d be nice to donate them to those needy or simply dispose of them without worry. But before you do that, you’d securely erase (wipe) all your stored data in the hard drives, because there are ways to retrieve the data there if you simply delete the files or even format them. Below are some stepped guides to do that for the most common operating systems, if you want more details, read here. Few key things to remember first:-
- Only mechanical hard drives, hybrid drives, USB drives and SD cards (as TRIM isn’t supported via the USB interface) need wiping. Usually wiping (typically by writing’0′ all over it) it once should be adequate. Some software have options for ‘military’ grade erasure – wiping it many times should not be necessary and will take ages!
- Solid State Drives (SSD) do not need wiping (just deleting all the files would do) as when you delete a file on a solid-state drive, the file is automatically wiped from the drive due to TRIM.
OK, now options for wiping/erasing hard drives, etc – Below first 2 options work for any drive, others depends on whether they are the boot drives (those consisting your boot files).
- by force – sledge hammer strikes to smash the hard drive would be most direct and fast, of course, you have to open up the computer case and find the hard drive first. And it’s not that good if you want to donate the computer to the needy. But that’s said to be the desperate action carried out on the US surveillance aircraft when it’s forced by the PLA to land in China.
- by hardware – this is also easy, just hook up your harddisk to some “Drive Eraser” (one model is shown above) and it takes care of the rest. But this thing is expensive starting from around US$200.
- for Non-boot drive (e.g. external drives) by utilities built-in by your OS (Operating System) or some free software downloaded from internet – this is simplest and just by clicking a few buttons.
- For Apple Mac’s (OSX) – just go to Disk Utility (search by Spotlight or under System Preference), select the disk you want to erase, click “Erase” option at the top menu, usually just choose wipe “once” option is adequate. Or use CCleaner for Mac, download by clicking the link.
- For Windows, you can use one of many drive-wiping tools. CCleaner for Windows is a particularly easy one to use — you just need the free version. Insert the USB drive or plug in the external hard drive, open CCleaner, and use the Tools > Drive Wiper feature. Another free and excellent one is Darik’s Boot And Nuke.
- Boot drive such as the internal drive in laptops and desktops – you need to go into special modes as you’d be erasing the drive that holds the booting files:
- For Apple Mac’s (OSX) – boot into Recovery Mode (turn off > wait 30 sec > switch power on and then Hold both the Command and R keys on the keyboard until you hear the chime noise.) Then use the Disk Utility application to erase the hard drive before reinstalling OS X (which you need internet access).
- On Windows 8 and 8.1, you can simply choose the “Reset your PC” feature and tell Windows to securely erase the drive. Choose the “Fully clean the drive” option to ensure none of your files can be recovered later.
- If you’re using Windows 7, Linux, or another operating system, you can boot your computer from a tool like DBAN (Darik Boot and Nuke) mentioned above. This tool will boot up and erase your computer’s hard drives, overwriting them with random data. You’ll have to reinstall Windows or Linux afterwards before anyone can use the computer again, of course (e.g. via an external drive, DVD, or just leave it to those who inherit it).