Macs are fairly reliable devices, and even have a built in recovery mode for you use in the event that something goes wrong.  However, in the event something is amiss with your Mac, or if you’re in IT working with a number of Macs, it’s important to have tools that you can use to reinstall Mac OS.  So in this article, we’ll show you how to create a working Mac OS install onto a USB flash drive.  The first method will be just using the Mac’s Terminal app with the other 2 options being with third-party applications.

Before you begin:

You’re going to need a few things before you begin:

1. A Working Mac
2. A USB flash drive with at least 16 gigs.  I personally recommend the Sandisk Cruzer line of flash drives and is what I’ll be using for this tutorial. NOTE: this will be erased so make sure you don’t have anything on the flash drive before using it or that you’re ok with it being erased.
3. A copy of the installer for the version of Mac OS you want to use.  I’ve pasted the links below for 10.13 “High Sierra” to the latest OS 13 “Ventura” at the bottom of this article.  Make sure you use the one supported for your machine.

Note you can put multiple installers on a single flash drive if the drive has enough space, they’ll just each take up a partition.  For now, we’re just going to show you one.  Once you’ve got the installer of your choice downloaded from Apple onto your Mac and have a working flash drive, then plug your flash drive into your Mac.

Do I need to erase my flash drive beforehand?

If your flash drive is already visible to the Mac in Finder, then you don’t need to worry about erasing it.  We have an article about how to securely erase your external drives if you want to check that out.  To condense that, you can open the Disk Utility app from the Utilities folder in the Applications.  Select the flash drive in the left sidebar under the External tag, then hit the Erase button from the top of of the window.  Then make sure you format it as a “Mac OS Extended (Journaled)” format, as well as a GUID partition if asked for it.  After it successfully erases, continue onto the next steps.

Option 1:  The Terminal

Open up the Terminal app, which can be found by going to your Application folder, then going to the Utilities folder, and clicking on the Terminal app.

Below are the codes you’ll need to type in for your specific versions of Mac OS.  NOTE: the name of the flash drive in this example is TEST, so please replace TEST with the name of your flash drive.

Copy the respective code into the Terminal, hit enter, then type in your administrator password, and hit enter once more.  Terminal should start by first erasing the drive, then loading the installer onto the machine.

Ventura

sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia --volume /Volumes/TEST

Monterey:

sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/TEST

Big Sur:

sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/TEST

Catalina:

sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/TEST

Mojave:

sudo /Applications/Install\ macOS\ Mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/TEST

High Sierra:

sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/TEST

Depending on a variety of factors, like how old your machine is, whether your using an older flash drive, etc. your speeds may vary.  I’ve seen it take anywhere from 5 minutes to 30.  So make sure you have enough time, maybe just grab a cup of coffee or tea.  Otherwise, when it’s done, you now have a bootable Mac installer and repair drive.

If you don’t want to mess with the terminal, we’ve got some alternatives for you.

Option 2: Install Disk Creator

Install Disk Creator is a tool that I personally like to use.  The app is really intuitive, easy to use.  After you’ve downloaded your preferred OS installer and plugged in your flash drive, open up the app.  The app will open and automatically find the installer you downloaded and display the installer icon with the name down below it.  If you have multiple installers in your Applications folder, it will typically pick the newest one.  That said, you can click the chosen installer’s icon to have it open your Applications folder and let you pick an alternative installer.

At the top of the screen you can pick the drive you want to install it to.  It will prompt you to erase the drive, then after typing in your administrator password it will begin to run.  On newer versions of Mac OS, it will ask if you’ll give permission for the app to access removable drives.  Hit OK, to give it access, and let it run.

As stated earlier, the time to completion can range from 5 to 30 minutes depending on various factors.  Regardless the app will notify when it has completed successfully and you can begin using the drive.

Download from: https://macdaddy.io/install-disk-creator/

Option 3: DiskMaker X

As a third option, you have DiskMaker X.

When you first launch the app, it will find any macOS installers on your machine, normally the Applications folder and the newest installer, and prompt you to select this installer or a different one.  Once you’ve selected the one you want, go ahead and hit OK.  It will then ask you for what drive you’re wanting to use, defaulting to a 16 gig thumb drive (even if that’s not what you have installed).  If you have one of those plugged in, then you can go ahead and hit the “16 gig USB thumb drive” button and move on.  If not, then select “Another kind of disk”, and then select the one you want in the popup menu.  It will give you a warning about erasing the drive, and then allow you to pick a “Light mood” or the “Dark side”.  This will be for the end.  Unlike the other options, when the completed drive is plugged into a Mac it will show a professional looking banner and icon for the installer, whereas the other options will show the raw file and folder structure to you, or just the installer icon.  The light and dark option reflects the icon and banner that it uses.  Pick your design, then type in your admin credentials to create the drive, and grant the app permission to access removable drives if prompted.  One downside to this app, and one reason this tool is not my preferred choice, is primarily because once it starts working on the flash drive, it tends to not give you a whole lot of information until it’s done. At that point it will display the professional working window.  If you really don’t care about loading bars, then you don’t have much to worry about.

Download from: https://diskmakerx.com/

And now you have 3 ways of making an install disk.  If you have a tool you prefer, feel free to let us know.

Download Mac OS Installers:

• OS 12, “Monterey: https://apps.apple.com/us/app/macos-monterey/id1576738294?mt=12
• OS 11, “Big Sur”: https://apps.apple.com/us/app/macos-big-sur/id1526878132?mt=12
• 10.15, “Catalina”: https://apps.apple.com/us/app/macos-catalina/id1466841314?mt=12
• 10.14, “Mojave”: https://apps.apple.com/app/macos-mojave/id1398502828?mt=12
• 10.13 “High Sierra”: https://itunes.apple.com/us/app/macos-high-sierra/id1246284741?ls=1&mt=12
• 10.12, “Sierra”: http://updates-http.cdn-apple.com/2019/cert/061-39476-20191023-48f365f4-0015-4c41-9f44-39d3d2aca067/InstallOS.dmg
• 10.11: “El Capitan”: http://updates-http.cdn-apple.com/2019/cert/061-41424-20191024-218af9ec-cf50-4516-9011-228c78eda3d2/InstallMacOSX.dmg

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