Deleting the contents of a hard drive (known as "formatting" in jargon) is a great way to prepare the memory drive for new use or to be sold or given away. Formatting a hard drive also allows you to use a different file system than the one you used previously, depending on your needs. This article explains how to format an external hard drive using a Windows computer or a Mac.
Steps
Method 1 of 3: Windows 10
Step 1. Back up any data you want to keep
If there are documents and information inside your hard drive that you need not to lose, be sure to copy them to another memory drive. You can transfer files to your computer's internal hard drive, to a USB stick, or to a clouding service, such as Google Drive, DropBox, OneDrive, or iCloud.
Step 2. Connect the external hard drive to the computer
Most external storage drives can be connected to a computer via a simple USB or firewire cable. Some external memory drives need to be powered in order to use them. If this is the case, connect the hard drive to the appropriate power supply.
Step 3. Open the "File Explorer" window by clicking on the icon
It features a yellow folder with a blue clip at the bottom. It is usually located at the bottom left of the desktop on the taskbar. If you can't find it, press the key combination ⊞ Win + E.
Step 4. Click on the entry This PC
It is listed in the left pane of the "File Explorer" window. The list of all internal and external hard drives connected to the computer will be displayed.
If the "This PC" option is not available, search for your computer name. It features a stylized monitor icon
Step 5. Select the hard drive icon to format with the right mouse button
A context menu will be displayed. If the memory unit under consideration has a specific name, you will see it listed in the "File Explorer" window. Otherwise, it will be labeled "USB Drive" or the make and model.
The amount of free space still available for each memory drive is displayed under the corresponding name. Select the hard drive whose storage capacity matches that of the external USB drive you want to format
Step 6. Click on the Format… option
It is one of the items listed in the context menu that appeared next to the hard drive icon that you selected with the right mouse button.
Step 7. Choose the file system to use
Click on the "File system" drop-down menu to be able to select the file system format to use for formatting the hard drive. You have three main options to choose from:
- NTFS is the most advanced file system in Windows, but may not be fully compatible with other operating systems such as macOS or Linux. Choose this option if you have planned to use the external hard drive by pairing it with Windows systems only.
- exFAT it is normally the default choice. This file system is compatible with all versions of Windows and with the most modern versions of macOS. Using a Linux computer you may need to install additional software to ensure compatibility. However, the exFAT format is supported by more devices than the NTFS file system. Choose this option if you plan to use the USB drive to store large files and also connect it to other devices, such as a Mac.
- FAT32 is an older file system that can handle files up to 4GB in size. However, it has the advantage of being compatible with a large number of devices. Choose this format if you usually work with files smaller than 4 GB and you need to use devices of various kinds (Windows, Mac, Linux).
Step 8. Click the Start button
It is located at the bottom of the "Format" window. A warning message will be displayed.
Step 9. Click the OK button
It is placed in the appeared pop-up. The latter simply warns you that by formatting the selected hard drive, all data inside it will be deleted. Clicking on the indicated button will start the unit formatting procedure. Depending on the computing power of the system and the size of the disk, the formatting process may take several minutes to complete.
Step 10. Click the OK button
It is placed in a pop-up that will appear on the screen as soon as the formatting of the disk is completed.
Method 2 of 3: Mac
Step 1. Back up any data you want to keep
If there are documents and information inside your hard drive that you need not to lose, be sure to copy them to another memory drive. You can transfer files to your computer's internal hard drive, to a USB stick or to a clouding service such as Google Drive, DropBox, OneDrive or iCloud.
Step 2. Connect the external hard drive to the computer
Most external storage drives can be connected to a computer via a simple USB or firewire cable. Some external memory drives need to be powered in order to use them. If this is the case, connect the hard drive to the appropriate power supply.
Step 3. Click on the magnifying glass icon
It is located in the upper right corner of the screen on the menu bar. A search bar will appear.
Step 4. Type the keywords Disk Utility.app into the search bar and press the Enter key
The "Disk Utility" app window will appear.
Alternatively, go to the system folder Utility stored in the directory Applications and click on the "Disk Utility" app icon.
Step 5. Select the external hard drive
All external storage drives connected to your Mac are listed in the "External" section of the "Disk Utility" window.
Step 6. Click on the Initialize tab
It is displayed at the top of the "Disk Utility" window.
Step 7. Name the external hard drive
This is the name that will be assigned to the memory unit after formatting is complete.
Step 8. Choose the file system format to use
Click on the "Format" drop-down menu to be able to select one of the following file systems:
- APFS is the most modern file system created by Apple, optimized for SSD solid state memory drives and USB sticks. Select this option only if the memory drive you want to format is SSD and only if you plan to use it exclusively with a Mac.
- Mac OS Extended is the default file system of all Macs since 1998. Select this option if your computer has a standard (mechanical) or hybrid hard drive, use an older version of Mac OS X, and if you plan to use the memory only with Mac.
- exFAT is the file system to choose if you want to ensure the compatibility of the external hard drive with multiple platforms, including Windows systems.
Step 9. Click the Initialize button
It is located in the lower right corner of the format window of the "Disk Utility" app. This will start the formatting process of the external hard drive. Depending on your system's computing power and disk size, this step may take several minutes to complete.
Step 10. Click on the "Eject" button next to the external hard drive name
When the formatting of the memory unit is complete, click on the indicated button located inside the left panel of the "Disk Utility" window. Do not disconnect the hard drive from the Mac without first waiting for the device eject procedure to complete.
Method 3 of 3: Using Third Party Software
Step 1. Back up any data you want to keep
If there are documents and information inside your hard drive that you need not to lose, be sure to copy them to another memory drive. You can transfer files to your computer's internal hard drive, to a USB stick or to a clouding service such as Google Drive, DropBox, OneDrive or iCloud.
Step 2. Visit the website https://killdisk.com/killdisk-freeware.htm using your computer's internet browser
This is the official website of the KillDisk program, a free app that allows you to erase the contents of a mechanical hard drive or SSD. It is available for both Windows and Mac. Programs such as KillDisk are safer, as in addition to erasing information from the disk, they overwrite it with random data to prevent it from being recovered.
There are also other very popular and used programs of this type, such as DBAN Drive Cleanser created by Acronis and CBL Data Shredder
Step 3. Click the Download for Windows button or Download for MacOS.
Choose the option that matches the operating system on your computer.
Step 4. Install KillDisk
By default, the files you download to your computer are stored in the folder Download on both Windows and Mac. Double-click on the EXE file of the KillDisk for Windows version or the DMG file of the KillDisk for Mac version, then follow the instructions that appear on the screen to complete the installation.
Step 5. Connect the external hard drive to the computer
Most external storage drives can be connected to a computer via a simple USB or firewire cable. Some external memory drives need to be powered in order to use them. If this is the case, connect the hard drive to the appropriate power supply.
Step 6. Launch the KillDisk app
It features a red shield icon with a white "@" symbol inside. Double-click on the Killdisk icon in the Windows "Start" menu or in the "Applications" folder on your Mac.
Step 7. Click on the icon of the hard drive you want to format
All disks connected to your computer are listed on the main KillDisk screen. The memory drive you select will be highlighted in orange.
Be careful not to select a hard drive or memory drive that you usually use, for example the volume that contains the Windows installation
Step 8. Click the Erase Disk icon
It is displayed at the top of the main window of the KillDisk app. It is characterized by a hard drive and a red triangle.
Step 9. Click on the Start button
It is located in the lower left corner of the pop-up that appeared.
If you have the full version of KillDisk, you will be able to select a more accurate and secure data erasing method by using the "Erase Method" drop-down menu. Also select the check button "Verify erasure of [percentage value] of each disk"
Step 10. Type the text shown under "Keyphrase" in the "Type keyphrase" field and click on the OK button
Type exactly the text displayed next to "Keyphrase", then click on the button OK. At this point, the procedure for deleting the data on the hard drive will begin. Since KillDisk is designed to overwrite information on the drive using random data, this step will take much longer to complete than the other formatting methods described in this article.
