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).

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.

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.

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.

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.

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.

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.

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”.