The Ultimate Guide to Formatting External Hard Drives for Mac

Using an additional hard drive with the Mac for the first time can be a bit tricky as far as compatibility is concerned. To work around it, you have to properly format the drive to make your information well-organized and compatible with macOS. 

Nevertheless, the question is this: what is formatting precisely, then? It is the stage where all the data from the storage device is being deleted and an alternative new file system is being set up. What this means to Mac users on the other hand is to select the most appropriate format in order to have compatibility, performance, and reliability when using the external drives. 

Why Should You Format External Drives for Mac?

There are three main reasons to format an external drive specifically for your Mac:

1. Ensure seamless compatibility with macOS and its supported file systems.
2. Optimize the drive’s performance and reliability by using an ideal format.
3. Securely erase all existing data for a fresh start or to recycle an old drive.

Before we get into the formatting process, it’s important to understand the different file system options available.

What Are The File Systems Available for Mac

Apple File System (APFS): This is the default way that modern Macs run on using the macOS operating system with newer versions. On the top of the list of converting benefits that APFS offers are built-in encryption, sophisticated snapshots, and rationalized storage. It’s not, though, the same: that the new version of the operating system has no backward compatibility with the older Macs which are not Apple.

Mac OS Extended (HFS+): A more previous one but not so advanced that would be used by everyone in Macintosh computers and devices. While it does not offer the advanced qualities of APFS, HFS+ continues to be the go-to file system for a majority of users.

exFAT: This format is a perfect choice for cross-system compatibility (Macs, Windows PCs, and so on). It is great if you take into account the fact that you can mount external drives across various operating systems. Anyway, exFAT does not have journaling, which ensures the features of Macs.

How to Format External Hard Drives on Mac

It is important to take a backup of your external hard drive before formatting. However, for unwanted file deletion or format, you can use data recovery tools designed for Mac to regain access to those lost files. With that being said, let’s now take a look at how to format external HDDs in Mac.

Formatting with Disk Utility

1. Launch Disk Utility (Applications > Utilities)
2. Select your external drive from the sidebar

3. Click the “Erase” button
4. Choose the desired format (APFS, HFS+, exFAT) based on your needs
5. Optionally, set a new name for the formatted drive
6. Click “Erase” again to execute the formatting process
7. Verify the new format under the drive’s information

For advanced users, Disk Utility also allows you to create multiple partitions on the same drive (ideal for dual-booting systems or separating backups) as well as enable encryption using FileVault for enhanced security. 

Formatting Via Terminal

While Disk Utility provides a user-friendly graphical way to format drives, more advanced users may prefer the command line approach using Terminal. This can be handy for scripting, automating tasks, or if you simply prefer the Terminal interface.

To format an external drive from Terminal:

1. Connect the external drive to your Mac.
2. Launch Terminal (Applications > Utilities > Terminal).
3. Type “diskutil list” and press Enter. This will list all storage devices connected to your Mac. Identify the disk identifier (e.g. /dev/disk2) for your external drive.
4. Run the format command, replacing the specifics with your desired options:
5. sudo diskutil eraseDisk [format] [name] [identifier]

For example, to format the disk2 device as exFAT named “BackupDrive”:

sudo diskutil eraseDisk exFAT BackupDrive /dev/disk2

You’ll be prompted to authenticate with your admin password. Enter it when asked. Terminal will show the format progress. Wait for it to complete successfully.

Some key things to note:

• Replace [format] with the file system format code (e.g. exFat, APFS, HFS+, MS-DOS)
• [name] is the name you want to give the formatted drive
• Properly identify the [identifier] for your target external drive

Since a single incorrect character can cause major problems, the Terminal approach requires extra caution. But it provides powerful, scriptable control for advanced users comfortable with command line interfaces.

Which File System You Should Choose

If you plan to use the formatted drive as a Time Machine backup destination, macOS actually prefers HFS+ or APFS (encrypted) formats. Follow Apple’s guides to properly configure your new backup drive.

Bootable installer drives for installing macOS also have specific format requirements, typically requesting MacOS Extended.

And for storing large media files like videos or photos, formats like APFS or exFAT are recommended to optimize read/write speeds.

Troubleshooting and Data Recovery

Sometimes formatting can fail due to unreadable disks or other errors. If your drive isn’t being recognized or you encounter issues, refer to Apple’s support documents and advanced troubleshooting advice.

Backups should always be your first line of defense. But, if you have accidentally formatted hard disk, don’t worry. Data recovery software like Disk Drill, PhotoRec, Testdisk, etc. offer ways to potentially rescue lost files after unintended formats. Just know that recovery is never 100% guaranteed.

How to Give Your External Hard Drive a Performance Boost

Beyond just choosing the right format, you can further optimize an external drive’s performance by:

1. Defragmenting to consolidate fragmented files
2. Enabling journaling to protect against corruption
3. Enabling TRIM support to allow for better handling of data
4. Following best practices like ejecting properly and avoiding overheating

When to Reformat Your External HDD for Mac

You’ll want to re-format an external drive if you plan to repurpose it for different needs, notice performance issues, or run into inexplicable errors that could be resolved by wiping it clean. When in doubt, a secure erase and reformat may resolve persistent problems.

The right format can make or break your external drive experience on Mac. By understanding your options and following the proper formatting process, you’ll ensure peak performance, compatibility, and peace of mind when using any external storage with your Mac.

FAQ

Do I need to reformat an external drive for Time Machine backups?

Not necessarily. Time Machine can work with drives formatted as Mac OS Extended (HFS+) or APFS. However, following Apple’s recommendations for an ideal backup disk format is advisable.

Can formatting fix external drive corruption or disk errors?

Formatting can potentially fix some logical corruption issues with the file system, but not physical drive problems. Scan with Disk Utility first to diagnose the underlying issue.

Can I format an external SSD the same way as a regular hard drive?

Yes, the formatting process is the same for both solid-state drives (SSDs) and traditional hard disk drives (HDDs). However, SSDs may benefit from specific optimization settings like TRIM support.