Coolest Guides on the Planet

coolest guides on the planet

Coolest Guides On The Planet

  • Home
  • macOS
  • WebDev
  • All Posts
  • Contact

How to format a USB external disk for Mac OSX using Disk Utility

July 28, 2013 13 Comments

All external USB disks can be formatted to work on Mac OSX, but not always straight out of the box.

In this tutorial we look at formatting disks via the GUI app called Disk Utility and its equivalent command line tool diskutil. This will work in all modern versions of Apple Mac OSX including 10.9 Mavericks, 10.8, 10.7 and 10.6.

Initially external disks may be formatted for Windows and after you connect it to your Mac it appears in the device list in the Finder, but is a read only disk meaning that you can’t write to it in its current format.

usb disk -write-mac

The when the disk is selected in the finder bottom left symbol with the crossed out pencil means that the disk can only be read not written to. Why this is, is because they come formatted as Windows NTFS drive which OSX can only read, so we need to reformat them so we can read and write – thats where a handy utility called Disk Utility comes to the rescue.

Disk Utility

disk-utility

Disk Utility is found in /Applications/Utilities/Disk Utility.app, open it and select your external disk in the list on the left.

There are 2 items (or more) for each disk, you have the actual disk and the volume of the disk, the example below has the Disk Named 2 TB WD Elements and the Volume is named Elements, this example uses the Volume which will in turn also format the Disk.

disk-utility-format osx

 

Then below you will see the Format type which will be NTFS or possibly MS-DOS (FAT), we need to reformat the volume and make the format Mac OS Extended (Journaled).

Reformatting the Disk

Still with the external disk selected in Disk Utility go to the Erase tab, select Mac OS Extended (Journaled) from the format dropdown, choose to name the disk and then click Erase.

disk-utility-format-osx extended

And there you have it one read and writable disk ready for OSX.

The Security Options option next to erase can control how the disk is erased by zeroing out all the blocks on the disk, this then make it impossible to salvage any previous data, with new disks this is not necessary.

Also the other format option Mac OS Extended (Case-sensitive, Journaled) in the dropdown would allow you have same name files or folders in the same location with a mix of case like ‘red’ and ‘RED’, this is popular in the Linux disk format and also possible on OSX but not the default on OSX shipped disks.

Doing it on the line

You can also do this using the command line using the tool diskutil which is the command line interface to Disk Utility, launch Terminal, Applications/Utilities/Terminal – to see a list of your disks:

diskutil list

and the results are similar to:

neilg@[~/Sites/wp2]: diskutil list
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            499.2 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *2.0 TB     disk2
   1:               Windows_NTFS Elements                2.0 TB     disk2s1
/dev/disk3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.1 GB   disk3
   1:                        EFI EFI                     209.7 MB   disk3s1
   2:                  Apple_HFS Macintosh HD            250.0 GB   disk3s2
   3:                  Apple_HFS target                  249.0 GB   disk3s3
   4:                 Apple_Boot Recovery HD             650.0 MB   disk3s4

This gives us a lot of information including the disk identifiers, size of disk and partitioning scheme. So in this example we will reformat the actual disk, disk2 using the command:

diskutil eraseDisk JHFS+ BackupMaster disk2

Here the command diskutil eraseDisk does the erasing, format is expressed as JHFS+ which is the Mac OS Extended (Journaled) and disk is named BackupMaster and the actual target disk is defined by its identifier disk2. The Terminal will result in this output:

Started erase on disk2
Unmounting disk
Creating the partition map
Waiting for the disks to reappear
Formatting disk2s2 as Mac OS Extended (Journaled) with name BackupMaster
Initialized /dev/rdisk2s2 as a 2 TB case-insensitive HFS Plus volume with a 155648k journal
Mounting disk
Finished erase on disk2

And there you have it one formatted disk ready to go.

Cats: macOS

Tags

3gs 10.6 apache backup baseband boot clean urls cpanel css curl custom database drupal el capitan git Google image instadmg ios iphone jailbreak keys lion mac macos mojave macos sierra menu mysql OSX panda php phpmyadmin private public redirect redsn0w remote rsa SEO shell ssh terminal unstoppables upgrade urls

Donate a Beer to the Coolest Guides

Get Beaver Builder Now!

Discuss

3gs 10.6 apache backup baseband boot clean urls cpanel css curl custom database drupal el capitan git Google image instadmg ios iphone jailbreak keys lion mac macos mojave macos sierra menu mysql OSX panda php phpmyadmin private public redirect redsn0w remote rsa SEO shell ssh terminal unstoppables upgrade urls
Get DesktopServer

Lynda

Lynda.com Online Training Videos

TreeHouse

smlinks

Learn WordPress
osx-modify-shell-path

How to Add to the Shell Path in macOS Big Sur and Catalina using Terminal

October 19, 2019

virtual-hosts osx 10.10 yosemite

Set up Virtual Hosts on macOS Catalina 10.15 in Apache

October 19, 2019

Installing Homebrew on macOS Catalina 10.15, Package Manager for Linux Apps

October 18, 2019

Where is the bash shell in macos Catalina?

October 12, 2019

Refine your search

  • All
  • Modules
  • Themes
  • Documentation
  • Forums & Issues
  • Groups

RSS ars technica

  • Matter update may finally take the tedium out of setting up your smart home
  • Cue: Apple will add AI search in mobile Safari, challenging Google
  • Apps like Kindle are already taking advantage of court-mandated iOS App Store changes
  • Spotify seizes the day after Apple is forced to allow external payments
  • Apple and Meta furious at EU over fines totaling €700 million

RSS mac surfer

  • Tot is new text editor for Mac, iPhone, and iPad focused on constraints and ease of use
  • TiPbITS: Google Drive Sorting Can Hide New Documents
  • How to take a screenshot on a MacBook Pro
  • How To Create Simple Animation With Mac Keynote
  • Last Week on My Mac: Virus pandemics

Donate

Copyright © 2025· Neil Gee - All Rights Reserved - Hosted by Runcloud

Copyright © 2025 · gee on Genesis Framework · WordPress · Log in