How To Create Bootable Installer For macOS

There are various reasons why you would need a macOS installer. Maybe you need it to reinstall macOS to fix a problem in your system or perhaps you’re planning to sell or hand down your old Mac to a new owner. It’s also possible that you’re the recipient of that old Mac. Similarly, there are also various ways to reinstall macOS. Aside from using recovery mode to reinstall macOS, you can also choose to make Mac boot from USB. In this article, we’ll show you how to make bootable USB so you can install macOS or an older version of it in case you can’t or don’t want to reinstall using recovery mode and other methods.

What You’ll Need to Create a Bootable MacOS Installer

There are two primary items you need to create a bootable USB to reinstall macOS. First, is the USB flash drive. You need one with at least 12GB of free storage. Even though the installation file size of High Sierra is 4.8GB, Apple recommends that you have 12GB storage available on your flash drive to allow for a more secure and stable installation. It will be best to use a Flash memory stick, but if you’re using a portable hard drive, we recommend USB 3.0, USB Type C, or Firewire. The next thing you need is the macOS installation files. You can get these from the Mac App Store.

How to Get MacOS Installation Files

Here’s how to get installation files if you are installing macOS High Sierra.

• Launch the Mac App Store on your Mac.
• Locate macOS High Sierra. If you have purchased or downloaded it before, you can look for it in your Purchased tab.
• Click Download. You will get a message warning you that macOS 10.13 is already installed on the computer. Just click Continue.
• Your Mac will now download the installer file. It will be saved in the Applications folder. The downloading process may take some time, and the speed will depend on your Internet connection. The download process might be faster if you connect to the Internet via ethernet.
• If the installer automatically launches after the download has finished, choose Quit right away. You don’t want to commence the installation process because doing so will delete the driver.
• Go to Applications folder, which you can access via Finder.
• If you are creating a bootable installer for an older macOS version, you can also look for its installation files in the Purchased tab.

How to Create a Bootable MacOS Installer

Now, here’s how to create a bootable USB for macOS.

• Connect your USB flash drive to the computer.
• Open Terminal, which can be found in the Utilities folder within the Applications folder. For the purpose of this article, we will assume that the installation files are still in your Applications folder and your USB flash drive’s name is USBBoot. Replace USBBoot accordingly when you do these steps yourself.
• Type or paste the following commands in Terminal if you are installing High Sierra:

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install\ macOS\ High\ Sierra.app

• Type or paste the following commands in Terminal if you are installing Sierra:

sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install\ macOS\ Sierra.app

• Type or paste the following commands in Terminal if you are installing El Capitan:

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app

• Type or paste the following commands in Terminal if you are installing Yosemite:

sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install\ OS\ X\ Yosemite.app

• Type or paste the following commands in Terminal if you are installing Mavericks:

sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install\ OS\ X\ Mavericks.app

• Press Return.
• Type in your administrator password when asked. Press Return. Note that Terminal will not show any characters as you type your password.
• Type Y when prompted to confirm that you want to erase the volume. Press Return again. The terminal will now show the progress as the bootable installer is being created.
• The Terminal will tell you when the process is done. Your flash drive will now have the name of the installer you created, for instance, Install macOS High Sierra.
• Quit Terminal and eject the USB flash drive or hard drive.

After reinstalling macOS, ongoing system maintenance can be beneficial. Tools like Outbyte macAries aim to assist in this, but be sure to confirm if it suits your needs for Mac care.