There are many reasons why you might want to create a bootable macOS Big Sur USB installation drive. For example, if you need to update frequently or clean install macOS on multiple Macs, having a bootable installer drive can make your job pretty simple. It can also be helpful if you want to downgrade from the macOS 12 Monterey beta and revert to the stable macOS Big Sur version. That said, let me show you how to create a macOS bootable installer drive.
How to Create a Bootable macOS Big Sur USB Install Drive (2021)
First, make sure you have a USB flash drive with at least 16GB of storage. Considering that every modern Mac comes with USB-C, a USB drive with a USB-C connector should be preferred. In terms of both speed and efficiency, SanDisk’s flash drives are top-notch. you can choose Sandisk 64GB Ultra Flair for $11 and Sandisk 64GB Ultra Dual Drive Luxe for $13.89 on Amazon.
Be warned that you will need to erase your drive and format it as Mac OS Extended (Journaled). You can do this in the Disk Utility app located in the Applications -> Utilities folder. Use the table below to learn how to create a bootable macOS Big Sur USB installation drive.
Download macOS Big Sur Setup Software
Another basic requirement is macOS Big Sur installer Software that you can download from the Mac App Store.
- Launch the Mac App Store and search for macOS Big Sur.
2. Now, “To obtain” button.
3. Next, Software update system preference will open. Click “downloadPress the ” button to start downloading the macOS Big Sur installer software.
Make sure you don’t click the Continue button after the download is complete and the installer has started. You can exit the installer by pressing the Command+Q shortcut. Next, go to the Applications folder to check it out. “Install macOS Big Sur” Application that you can use to make bootable drive.
Use Terminal to Make a Bootable macOS Big Sur Drive
Terminal makes it easy to make an external drive a bootable macOS installer. Therefore, even if you are not very familiar with it, you can easily get the job done.
1. Connect the US drive to your Mac to get started. I would like to point out that in this guide, I use “Drive” as the name of the external drive. For ease of use, you can replace “Drive” with the name of your drive. Then start terminal (Applications -> Utilities -> Terminal) applet. You can use Spotlight to launch it quickly.
2. Now, select and copy the following command:
sudo /Applications/Install macOS Big Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/Drive -- /Applications/Install macOS Big Sur.app
3. Next, paste the copied code In Terminal on your Mac. make sure you change “To spread” In the name of your USB drive. Next, Return key.
4. If prompted, enter your system password and Return. Terminal may warn you that your external USB drive will be erased. you need to write “TO” and press Return to continue.
5. Now, a warning might appear like this: “The terminal wants to access files on a removable volume.” Click “OK” in the pop-up window.
Terminal will clean your USB drive and then copy the Big Sur installer file to your drive. The whole process may take a few minutes. Finally, you will see a message saying your driver is ready for use in Terminal. If you want, you can also use Terminal to create the macOS Big Sur ISO file.
How to Boot macOS Big Sur from USB Installer Drive
After you create the bootable macOS Big Sur installer drive, you can easily boot your Mac from it. We are now very close to downgrading from macOS 12 beta to macOS 11 Big Sur. Follow the steps below:
- Make sure the external drive is plugged into your Mac. Then restart your Mac and option/sub key. You have to press the key until the Apple logo first appears on the screen and the Startup Manager opens.
2. When the Startup Manager appears, select your external drive. Now, your Mac Recovery Modeand a window with four options will appear.
3. Select Install macOS Big Sur to install Big Sur and keep the data intact. However, if you want to start over and delete data, “Disk Utility” and then install macOS Big Sur.
If you enter Disk Utility, format your hard drive and then exit the application. It will take you back to the Recovery mode window where you can perform the operating system installation.
Update macOS Installer Driver
Sometimes, you may need to update the installer driver to use it to clean install macOS Big Sur on your Mac machine.
- connect External Drive and then Restart your Mac and hold Option key While the Mac is booting (when you see the Apple logo on the screen).
2. Next, your Mac Startup Manager with available boot drivers. Now, click on the external drive and press Return. Next, a popup will appear saying: “A software update is required to use this startup disk. Now you can update or choose another startup disk.” Click update button.
Your macOS device will restart once the update starts running. Note that the update will take a few minutes to complete.
Change Mac Security Setting to Use External Startup Disk
macOS comes with a security setting to not allow external startup disk. If enabled, you will need to change the security setting to allow booting from external USB or removable media drives.
1. To get started, Restart your Mac. After that hold Command+R During the boot process to put your Mac into Recovery Mode.
2. Now, your Mac macOS Utilities window. Click “VehiclesSelect the ” menu and select “Launch Security Utility“.
3. Then an alert will appear saying: “Authentication Required. You will need to authenticate as Administrator to change boot security settings.” Next, “Enter macOS Password” and enter the username and password.
4. Under Allowed Boot Media section, “Allow boot from external or removable media“. Then restart your Mac and follow the steps above to boot from the USB drive.
Create and Use a Bootable macOS USB Install Drive
Well, that’s all! So you can create and use a bootable macOS Big Sur USB installation drive. The same process applies to older generation macOS versions as well. With a bootable USB installation drive at your disposal, cleaning up macOS on your Mac machine becomes effortless. If you need to do updates or clean the operating system more often, this should be the preferred way.
In the meantime, do you have any relevant feedback or questions? If yes, feel free to share it in the comments section below.
