How to wipe a hard drive (HDD or SSD) securely
Anyone who sells or disposes of a used computer for private or business purposes should wipe the hard drive thoroughly beforehand. Since data remains even on formatted hard drives, it is recommended to use additional tools such as DBAN or integrated on-board tools such as DiskPart (Windows) or Disk Utility (Mac).
Why formatting the hard drive is not enough
Anyone sorting out a laptop or computer needs to be aware of one thing: Even formatting the hard drive does not completely remove all data and makes it possible for data to be recovered. Even if professional knowledge and special data recovery tools are required for this, there is a risk that sensitive data will fall into the wrong hands.
With a quick format, only the addresses of the stored data in the table of contents are deleted, but not the file itself. A normal format, on the other hand, sets the file locations to zero, which, with the right knowledge, also enables data recovery. If you want to be on the safe side, it’s not enough to simply empty the digital recycle bin, format the hard drive under Windows, reset your Mac, or delete a partition. Thorough deletion with additional tools is required.
Wipe an HDD or SSD securely: What is the difference?
Before we show step by step how to wipe a hard drive on Mac, Windows 10 and 11, it is necessary to clarify whether it is an HDD hard drive or SSD storage. Both HDD (Hard Disk Drive) and SSD (Solid State Drive) are used for data storage, but they work in different ways:
- HDD: These are hard drives with physical, moving components such as rotating magnetic disks to store data. They do not operate silently and are more sensitive to shock. On the other hand, they are cheaper and offer more data recovery options.
- SSD: These are not classic hard drives, but a storage medium that uses multiple flash memory chips with semiconductor cells without mechanical, moving components for storage. They operate silently, are more robust, smaller, and significantly faster than HDDs. However, in the event of data loss, recovery is difficult.
Another essential difference between HDD and SSD is the way you wipe the HDD. When thoroughly erasing HDDs, on-board system tools or add-on tools are used, which overwrite the memory with random data according to set patterns. These are then deleted, which makes data recovery almost impossible. In the case of SSD storage, overwriting the data is not sufficient, as there is no clear assignment between physical memory cells and their associated sector address in flash media, and spare memory cells are also used.
To find out whether your device has an HDD or an SSD, look in the technical data sheets/stickers/labels or under “Drives” (Windows) or “System Information” (Mac).
Securely wipe a hard drive: Step by Step
Adhere to the following steps to wipe your hard drive on Windows 10, 11 or Mac. Attention: Before you wipe your hard drive data irretrievably, make a backup of all important data.
Windows 10 and 11: Wipe HDD
If you would like to delete an HDD hard drive or partitions in the Windows operating systems 10 and 11, Windows offers the command line tool DiskPart for this purpose. DiskPart is not only handy to partition Windows 11 hard drives, but also if you want to make all hard drive data unreadable by overwriting it. You can use it to delete even the recovery partition, but not the active Windows system partition. To do this, you must remove the hard drive, connect it to a secondary computer, and run DiskPart through it.
With third-party tools like the free DBAN (Dariks Boot and Nuke), on the other hand, you can make a USB stick bootable to clean all files and partitions. After that, you can install a new, clean system like Windows 11.
We will introduce both methods below.
Step 1: Note that you need to run DiskPart with administrator privileges. To do this, type “diskpart” in the Windows search and click “Run as administrator”.
Step 2: Note that the Windows system partition can only be overwritten if you are not currently running it. To overwrite the desired disk, type one of the following DiskPart commands as needed and press [Enter.]
- list disk: All disks found on the system are listed.
- select disk <number>: Switches directly to the disk in question
- detail disk: Displays details of the disk in question
- clean all: Command to overwrite all sectors of the selected disk with zeros
- clean: Deletes only the first and last Mbyte of the partition.
Although DBAN has not been maintained for some time, the free tool is still considered effective.
Step 1: First, create a bootable USB stick with DBAN. When you insert it, DBAN will start before booting your operating system. You can read through the instructions and then press [Enter] to start.
Step 2: In the following menu, use the arrow keys to select either the entire hard drive for deletion or individual partitions. Confirm the selection by pressing the space bar.
Step 3: Press [M] to select the desired method of deletion. You can select a single overwrite or multiple overwrites with multiple patterns. The following methods are available for selection:
- Quick Wipe: Overwrite with zeros
- Canadian RCMP TSSIT OPS-II Standard: Overwrite with random patterns of ones and zeros.
- DoD Short: Overwrite three times with ones, zeros, or random patterns
- DoD 52220,22-m Standard: Overwrite seven times with random patterns
- Gutmann Method: Overwrite 35 times with random patterns
- PRNG Stream: Overwrite once with random data
Step 4: Start the selected wipe process by pressing [F10]. The process requires a longer time. You should exit the program only after successful deletion.
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Windows 10 and 11: Wipe SSD
Usually, SSD manufacturers offer programs in the support section that allow you to wipe your flash media via the ATA Secure Erase option. These include “Samsung Magician” or “Sandisk SSD Dashboard”, for example. Note that the SSD does not serve as a boot medium, but must be connected as a second drive or mounted with an external medium. Alternatively, manufacturer software also offer the option of creating a bootable USB stick. If there is no management tool from the manufacturer, you can also use a manufacturer-independent Linux live system like Parted Magic. We will briefly introduce both methods.
ATA Secure Erase
Step 1: Download the associated management program for your SSD storage device from the manufacturer’s support site. In some cases, the ATA Secure Erase function can be used directly in Windows in the BIOS or via the UEFI interface. If this function is not available, boot your SSD via another data medium, e.g. a bootable USB stick.
Step 2: After booting the manufacturer’s management tool, follow the program’s instructions to run the Secure Wipe function or, depending on the manufacturer, the sanitize function to thoroughly wipe the SSD.
Step 1: Download Parted Magic for free from the manufacturer’s site or a trusted platform. Burn the program’s image files to a CD or create a bootable USB stick with it. Then, boot your system from the external media.
Step 2: In Parted Magic’s desktop menu, go to “System Tools” > “Wipe Disk”.
Step 3: Select “Internal: Secure Erase command writes zeroes to entire data area”. Next, specify the drive to be wiped. You may get a message that the SSD is “frozen”. In this case, click on “Sleep”, wake up the computer, and select “System Tools” > “Erase Disk” again.
Step 4: Confirm the process by clicking “OK”. After that, all data remnants of the selected SSD will be irretrievably deleted.
Mac: HDD and SSD
Step 1: Although recent Macs are almost all equipped with SSDs, HDDs can also be found in older models. If you want to wipe your HDD or SSD, use Spotlight search to find and open “Disk Utility”.
Step 2: The program lists all recognized internal and external storage devices. Select the drive in question and click “Wipe” from the top menu.
Step 3: In the following window, select “Security options...”.
Step 4: A new menu window will open where you can use a slider to specify how thorough the data deletion should be. You can choose between “Fastest” and “Most secure”. Then confirm with “OK” and start the deletion process in the next window by clicking on “Delete”.
Be sure to remove the link to your iTunes account under the “Authorizations” of your iTunes/Music account before wiping. Also, disable Filevault via “System Preferences” > “Security & Privacy” > “Filevault” before wiping.