Using Apple’s “Terminal,” you can create a macOS High Sierra bootable USB installer. This installer can be used to perform a clean installation of macOS High Sierra on a compatible Mac.
macOS High Sierra is compatible with the following Macs:
- MacBook (Late 2009 or newer)
- MacBook Pro (Mid 2010 or newer)
- MacBook Air (Late 2010 or newer)
- Mac mini (Mid 2010 or newer)
- iMac (Late 2009 or newer)
- Mac Pro (Mid 2010 or newer)
For a detailed list of macOS High Sierra system requirements, visit the link below:
To create the macOS High Sierra bootable USB installer:
First, download the latest version of macOS High Sierra from the App Store. When the download is complete, the macOS High Sierra Installer application will launch. You can close the Installer application. Locate the macOS High Sierra Installer in the “Applications” folder of your Mac HD. The file will be called “Install macOS High Sierra.” Leave the macOS High Sierra Installer in the default location. This is important for later on.
Next, connect a USB Flash drive to your Mac. The USB Flash drive should have a storage capacity of at least 8GB. Make sure the USB Flash drive does not contain any files or documents you wish to keep. As part of the process to create a bootable USB Flash installer for macOS High Sierra, the USB Flash drive will be formatted (all data will be erased). Once the USB Flash drive is connected and has mounted onto your desktop, change the name of the drive to “Untitled.” Again, this is important for later on.
Launch “Terminal.” You can do this by going to the Finder, select “Go” from the menu bar then “Utilities.” Within “Utilities” double-click on “Terminal.”
Copy and paste the command line below into the “Terminal” window. Be sure to copy the command line accurately and in its entirety.
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled –applicationpath /Applications/Install\ macOS\ High\ Sierra.app
After pasting the command line, “Terminal” will prompt you for your computer’s password. Enter your password then press the return/enter key on your keyboard. You must use an account with Administrator privileges.
“Terminal” will ask you to confirm that you want to erase the USB Flash drive. Enter “Y” for Yes then press the return/enter key on your keyboard. “Terminal” will format the USB Flash drive (you will see the message “Erasing Disk: 0% . . . 10% . . .”) and then proceed with copying over the macOS High Sierra Installer files and make the USB Flash drive bootable (you will see the message “Copying installer files to disk . . .”). This process may take some time to complete so be patient. Once the process is complete, “Terminal” will display “Copy complete” followed by “Done” and take you back to a Terminal command prompt. If there are no error messages, you can close out of “Terminal.”
Your macOS High Sierra bootable USB Flash drive should now be ready. You can test the USB Flash drive by restarting the Mac and holding down the Option key during restart. On startup, you should be prompted to select the drive that you want to boot from (either the internal hard drive/SSD or the USB Flash drive). Select the USB Flash drive to make sure the drive works properly. After the USB Flash drive boots successfully into the macOS High Sierra Installer, you can exit the installer, restart the Mac and boot normally to your internal hard drive/SSD.
- After downloading the macOS High Sierra Installer, make sure to leave the Installer file in its default location (the “Applications” folder). The Terminal command line will not work if you move the Installer file.
- Make sure the USB Flash drive is renamed to “Untitled.” The Terminal command line will not work if the USB Flash drive is named differently.
- If you are having problems creating a macOS High Sierra bootable USB Flash drive using the current USB Flash drive, try a different USB Flash drive. Some USB Flash drives may be problematic.