Formatting (completely erasing data) a hard drive is a good way to clean up your hard drive or get rid of data if you're selling or gifting a drive. You can also change the file system of the disk during the formatting process. In this article, we'll show you how to format your external hard drive on Windows and macOS.
Steps
Method 1 of 3: Formatting in Windows 10
Step 1. Back up important data
If there is data on the disc that you want to keep, copy it to another storage medium, such as your computer's internal hard drive or a USB flash drive. You can also upload data to cloud storage, for example, Google Drive, DropBox, OneDrive or iCloud.
Step 2. Connect your external hard drive to your computer
Most external hard drives can be connected to a computer using a USB or FireWire cable. In some cases, the external hard drive also needs to be connected to the AC adapter.
Step 3. Open an Explorer window
Click on the folder-shaped icon with a blue clip; this icon is on the taskbar at the bottom of the screen. If you don't see the icon, press ⊞ Win + E to display it.
Step 4. Click on This PC
It's in the left pane. A window will open displaying all external and internal hard drives connected to the computer.
If you don't see the This PC option, look for your computer name. It will be marked with a monitor icon
Step 5. Right click on the external hard drive
A context menu will open. If the external hard drive has a name, it will be listed in File Explorer. Otherwise, the drive will be referred to as "USB storage" or as the brand and model of the drive.
The total and free capacities will be displayed under the disk name. Right click on the hard drive with the amount of free space that you have on your external hard drive
Step 6. Click on Format
This option is on the context menu.
Step 7. Select a file system
Open the File System menu and select the file system that will be used on the external hard drive. There are three main file systems to choose from:
- NTFS - This file system is compatible with Windows, but may not be writable on macOS and other systems. Select this option if you plan to use the external drive only on Windows computers.
- exFAT - as a rule, this file system is selected by default. It is compatible with all versions of Windows and the latest versions of macOS. With additional software, this system will work on Linux, which means that more devices support it than NTFS. Select this option if you plan to store large files on the disk and connect the disk to other devices, such as macOS.
- FAT32 is an outdated file system that can store files no more than 4 GB. It is compatible with a wide variety of devices. Select this option if you are not working with large files and are going to connect the drive to a variety of devices.
Step 8. Click on Start
This button is at the bottom of the Formatting window. A pop-up warning will appear.
Step 9. Click on Ok
This option is in a pop-up warning that states that all data on the external drive will be deleted. You will confirm your actions and start the formatting process, which will take some time (it depends on the performance of your computer and the size of the external hard drive).
Step 10. Click Ok
This button is in the window that will open when the formatting process is complete.
Method 2 of 3: Formatting on macOS
Step 1. Back up important data
If there is data on the disc that you want to keep, copy it to another storage medium, such as your computer's internal hard drive or a USB flash drive. You can also upload data to cloud storage, for example, Google Drive, DropBox, OneDrive or iCloud.
Step 2. Connect your external hard drive to your computer
Most external hard drives can be connected to a computer using a USB or FireWire cable. In some cases, the external hard drive also needs to be connected to the AC adapter.
Step 3. Click the magnifying glass icon
You will find it on the right side of the menu bar at the top of the screen. The search bar will appear.
Step 4. Type Disk Utility.app in the search bar and press ↵ Enter
Disk Utility starts.
You can also find Disk Utility in the Utilities folder, which is located in the Applications folder in Finder
Step 5. Select an external hard drive
All external hard drives are listed under the "External" section in the left pane of the Disk Utility window.
Step 6. Click on Erase
It's in the center and top of the Disk Utility window.
Step 7. Enter a name for the external hard drive
This name will be assigned to the hard drive when it is formatted.
Step 8. Select the disk file system
Open the Format menu and select one of the following file systems:
- APFS is Apple's latest file system optimized for solid state drives (SSDs) and flash drives. Select this option only if you have an SSD or flash drive and plan to use this drive only on Mac OS High Sierra or later.
- Mac OS Extended is Apple's standard file system introduced in 1998. Select this option if you have a magnetic or hybrid hard drive, if you are using an older version of macOS, and if you only plan to connect an external hard drive to Mac computers.
- exFAT - select this option if you are going to connect the hard drive to different devices, including Windows computers.
Step 9. Click on Erase
It's in the lower-right corner of the Format window in Disk Utility. The process of formatting the external hard drive will start. This process will take some time, depending on the performance of your computer and the size of the external hard drive.
Step 10. Click "Eject" next to the external hard drive
When the formatting process is complete, click Eject next to the hard drive name in the left pane of the Disk Utility window. Do not disconnect the drive from the computer until you remove it.
Method 3 of 3: Using disc erasing software
Step 1. Back up important data
If there is data on the disc that you want to keep, copy it to another storage medium, such as your computer's internal hard drive or a USB flash drive. You can also upload data to cloud storage, for example, Google Drive, DropBox, OneDrive or iCloud.
Step 2. Go to https://killdisk.com/killdisk-freeware.htm in your browser
This is the website for the free Killdisk disk erasing program (magnetic and solid state) and supports Windows and macOS. Such programs provide additional security because old data is overwritten with random numbers to prevent the recovery of deleted files.
Other popular data erasing programs are Acronis' DBAN Drive Cleanser and CBL Data Shredder
Step 3. Click on Download for Windows (Download for Windows) or Download for MacOS (Download for macOS).
Select the option appropriate for your operating system.
Step 4. Install KillDisk
By default, downloaded files are located in the Downloads folder. Double-click the downloaded EXE file (Windows) or DMG file (Mac), and then follow the instructions on the screen.
Step 5. Connect your external hard drive to your computer
Most external hard drives can be connected to a computer using a USB or FireWire cable. In some cases, the external hard drive also needs to be connected to the AC adapter.
Step 6. Launch KillDisk
To do this, double-click the @ icon in the red background in the Start menu (Windows) or in the Applications folder (Mac).
Step 7. Click on the disk you want to erase
All disks connected to the computer will appear in the main KillDisk menu. The selected drive will be highlighted in orange.
Be careful not to select another drive, such as the Windows drive
Step 8. Click on Erase Disk
It's at the top of the KillDisk window. It is marked with a hard drive icon with a red triangle.
Step 9. Click Start
This button is located in the lower left corner of the pop-up window.
If you have a registered version of KillDisk, you can choose how to erase the data in the Erase Method menu. You can also check the box next to “Verify erasure of [disk percentage] of each disk”
Step 10. Enter your passphrase and click Ok
The passphrase is located above the field for entering it. Enter the phrase as it appears, and then click OK. The process of erasing the disc will start. Since the program will overwrite the old data with random numbers, the process will take significantly longer than the usual disk formatting.