How to Format an External Hard Drive for a Mac

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Bernard Perron
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External hard drives are great for storing files that you don't use frequently. Since many external drives are designed to work with Windows, there's nothing more frustrating than finding out that your drive and your Mac are incompatible.

Luckily, by formatting your external hard drive, you can use it to save your Mac files.

Read on to learn how to format or partition your external hard drive for Mac.



How to Format an External Hard Drive for a Mac

Follow these steps to format your external hard drive using "Disk Utility":

Notes: This process will delete all the files you currently have on the drive. Be sure to save any files you want to keep elsewhere before you begin.

  1. If you're using a MacBook to format the drive, make sure it's either fully charged or connected to a power supply to ensure it doesn't shut down in the middle of the process. Plug your external hard drive into your Mac.
  2. Once connected, a drive icon should appear on your desktop. If not, try opening the “Finder”. Then choose “Preferences”.
  3. Select the “General” tab, then make sure the “External Drive” box is checked.
  4. In the "Finder" window, select the "Applications" folder in the left pane.
  5. Choose “Utilities” then “Disk Utility”.
  6. In the left pop-up window, your external hard drive should appear listed under your Mac's internal drive under "External."
  7. Click on the first level of your external drive. Make sure you don't select the lower level of your external drive, as this will cause formatting issues. To be sure you have set the top level, click the right-pointing arrow to the left of the player icon.
  8. At the top of the pop-up window, select "Erase". Next, fill in the details of your external hard drive.
  9. Add a name to your hard disk, then define its format:
    • For an SSD, choose "APFS (Apple File System)". This option may not be available if you haven't formatted the drive yet, so choose another one and then reformat it to APFS if necessary.
    • For compatibility between newer and older Macs, choose "Mac OS Extended (Journaled)".
    • To use the drive with Mac and Windows, select “ExFAT”.
  10. In the "Scheme" option, choose "GUID Partition Map".
  11. Now select the “Erase” button and wait for a few minutes while your hard drive is formatting.

How to Partition an External Hard Drive on a Mac

By partitioning your external hard drive, you can have separate drives for Mac, PC, and other operating systems. A partition provides dedicated space for a bootable backup of your operating system or Time Machine backup files. It will also help protect your drive if it gets infected with malware as it would be contained in a partition section.



Once your disk is formatted (see the steps above), you can partition it into two formats. This is ideal if you use a Mac and a PC and want to transfer files between the two operating systems via your external hard drive. Follow these steps to do so:

  1. With your external hard drive plugged into your Mac, navigate to "Disk Utility."
  2. Select your external hard drive, then choose "Partition" from the top menu.
  3. To create a partition, at the bottom of the pie chart, click on the plus sign (+).
  4. Select a name, format, and size for each partition. You can also drag the white dots at the edge of the circles to change the size of each partition.
  5. Click "Apply".

Additional FAQs

What is the best format for a Mac external hard drive?

If you want to use your external hard drive with both Mac and Windows computers, the best format to use is exFAT. By using exFAT, you can store files of any size and use them with computers made within the last 20 years.



However, if your external hard drive is only intended for use with Macs, Mac OS Extended (Journaled) would be the best option as it is compatible with all Macs.

What is the difference between Mac OS Extended and Mac OS Extended Journaled?

"Mac OS Extended" uses Mac format, needs a password and encrypts the partitioned disk. “Mac OS Extended Journaled” uses Mac format and folder names are case sensitive. For example, "Mac Files" and "MAC FILES" would be two separate folders.

Formatting your external hard drive is not difficult

External hard drives provide the extra space you need to store your digital content when your computer starts to fill up. Although there are many cloud-based storage solutions, storing your data this way is more reliable and ensures that you retain ownership of it.

Many external hard drives are designed for Windows. Luckily, by using the "Disk Utility" feature on your Mac, you can format your drive to not only work with new and old Macs, but Windows as well.

What type of format did you use? Tell us what you will use your reader for in the comments section below!

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