Advertisement
  1. Computer Skills
  2. macOS
Computers

How to Create a Bootable USB Drive for macOS Sierra

by
Difficulty:BeginnerLength:ShortLanguages:

macOS Sierra 10.12 is the thirteenth major release from Apple, released on 20th September 2016 as a free upgrade via the Mac App Store. It is a digital download of approx 5 GB. 

Whilst the process of downloading and installing an OS through the Mac App Store is straightforward enough, it’s painful for people with a slower internet connection, or if they’ve multiple Macs in their home.

If a Mac is having some issues a bootable USB of the OS can serve as an emergency disk. It is better than OS X Recovery as you don’t have to download the ~5GB installer data, first, to reinstall the OS or installer disk for Macs that does not support OS X Recovery.

In this tutorial, I'll show you two ways to install macOS Sierra onto a bootable USB drive.

Cost of Upgrade and Requirements

Before you get started, you’ll need

  • Software—macOS Sierra 10.12 installer app
  • Storage—USB 3.0 drive of 8GB or more, or an external USB hard drive, or a Firewire or Thunderbolt external hard drive
  • A copy of DiskMaker X

Locate the macOS Sierra Installer

Open the Finder window and navigate to Applications > Install macOS Sierra. Proceed and follow the next steps for creating bootable USB drive.

macOS Sierra installer in the Finder
macOS Sierra installer in Finder

Download macOS Sierra Installer

If you do not have the Install macOS Sierra app in the Applications folder, then you might have already upgraded to macOS Sierra. The installer application gets automatically erased after upgrading the Mac. To create a bootable disk, you need to have the installer app.

Step 1

Open the Mac App Store. Click on the Purchases tab, locate macOS Sierra and click the Download button.

Download Sierra or El Capitan OS from the App Store
Download Sierra or El Capitan OS from the App Store

Step 2

Once the download gets complete, you’ll see the installer window. Secondary-click, or two-finger tap with trackpad, on the running installer app from the dock and choose Quit.

macOS Sierra installer window The only way to quit this app is through Dock
macOS Sierra installer window. The only way to quit this app is through Dock

Step 3

Open the Finder window and navigate to Applications > Install macOS Sierra. Proceed and follow the next steps for creating bootable USB drive.

Command Line Method

Step 1

Insert the USB drive. Open the Disk Utility app. Select the USB drive and click the Erase button. 

Choose the Name as UntitledFormat as OS X Extended (Journaled) and select Scheme as GUID Partition Map. This option is used for all Intel-based Mac computers. 

Click Erase, then click Done.

Format USB drive with Disk Utility
Format USB drive with Disk Utility. 

Step 2

Launch the Terminal app. Copy the following command
sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ macOS\ Sierra.app

Breakdown of the steps:

If you closely follow the above command, they rely on basic syntax

createinstallmedia --volume volumepath --applicationpath installerpath

  • sudo—It’s a tool that is provided to allow regular (non-root) users to perform root tasks on a case by case basis
  • createinstallmedia—Use this command in Terminal to create the bootable installer. To make this work, the app installer should be in the Applications folder. The OS installer path varies for Sierra, El Capitan, Yosemite, and Mavericks. Consult the Apple Support article for documentation
  • volume — Replace volumepath with the path to the USB drive or other volume.
  • applicationpath — This is the path to the Install macOS app

Step 3

Go back to the Terminal and paste the above command.

Step 4

Terminal will ask for the user password. Terminal doesn’t display characters when you type it in. Press Return.

Step 5

It asks for the confirmation to erase the drive. Type Y and press Return.

Confirm the command with Y to erase the drive
Confirm the command with Y to erase the drive 

Step 6

You’ll see that Terminal starts erasing the drive, it then copies the installer files to the USB drive. This step can take few minutes to hours depending upon whether it is copying via USB 2.0 or USB 3.0.

Terminal automatically erasing and copying installer data to USB drive
Terminal automatically erasing and copying installer data to USB drive

Step 7

After copying, Terminal will display a Copy complete and Done notice. You can quit Terminal and the drive is ready to use.

terminal-complete-notice
Process completed in Terminal app itself

Step 8

Eject the USB drive before removing it from the Mac.

Automated App Method

If you’re not into Terminal, then the automated method using an app is going to be easier for you.

Step 1

Insert the USB drive. Open the Disk Utility app. Select the USB drive and click the Erase button. 

Choose the Name as UntitledFormat as OS X Extended (Journaled) and select Scheme as GUID Partition Map. This option is used for all Intel-based Mac computers. Click Erase, then click Done.

Erase USB drive in disk utility
Erase USB drive in disk utility

Step 2

Install DiskMaker X app. This app lets you create a bootable USB drive in a matter of minutes. You can use this drive to reinstall the OS on a freshly formatted drive, or install it on different Macs.

Step 3

Launch the DiskMaker app. It asks you the version of macOS you wish to make a boot disk of.

Choose the macOS version for which youd like to make installer disk
Choose the macOS version for which you'd like to make installer disk

Step 4

If finds the copy of the Installer app in the Applications folder.

Choose the installer in the Applications folder You have the option to use another copy
Choose the installer in the Applications folder. You have the option to use another copy

Step 5

Select the USB drive you wish to format. If you choose another kind of disk, only the chosen volume will be erased.

Choose the type of drive or another volume
Choose the type of drive or another volume

Step 6

DiskMaker X erases the disk.

Erase notification by diskmaker X
Erase notification by diskmaker X

Step 7

Enter the password of the user account.

Type in the user account password in the next screen after clicking Continue
Type in the user account password in the next screen after clicking Continue

Step 8

The process starts and can take some time to complete. It took around 5–6 mins to complete on Mac Mini 2012 with SSD and 10GB RAM copying to a USB 3.0 drive.

Step 9

The process completes. Now eject the USB drive before removing it from the Mac.

The bootable USB drive is ready to use
The bootable USB drive is ready to use

How to Boot from the Installer Drive

Step 1

Plug in the external USB drive you just created.

Step 2

Restart the Mac. Press and hold down the Option key while the Mac boots.

Step 3

The Mac will display the startup manager which will show you all the boot drives.

Click on the external USB drive and press Return.

Step 4

The Mac will display the OS X Utilities window. You can either install OS over the installed OS or format and reinstall the OS.

Choose external USB drive from the startup disk manager
Choose external USB drive from the startup disk manager

Conclusion

In this tutorial I have shown you two different ways to create a bootable USB drive for macOS Sierra. One is by command line and one using an app, DiskMaker X

Both methods offer ease of use and flexibility, so it’s up to you to choose a method. Don’t forget to label the USB drive onto which you install macOS Sierra and make sure to keep them safe.

Advertisement
Advertisement
Looking for something to help kick start your next project?
Envato Market has a range of items for sale to help get you started.