Apple will soon have a new version of macOS. It’s called Big Sur, and it’s version 11. To install it on multiple Macs, you can go to each Mac, connect to the App Store, download Big Sur, and then install it. Waiting for the installer to download, however, takes a long time, and it spreads over several Macs.
The best way to do this is to create a bootable installation station. You download the installer once, create the installer, and then use the drive to install Big Sur on your Macs. You can also keep the drive for future use.
In this article I will go through how to create a bootable MacOS Big Sur installation drive. But before I give instructions on how to make the drive, I will go through the items you need and how to get them.
These instructions are for the public beta of macOS Big Sur. This article will be updated when the operating system is officially released this fall.
Important Note: These instructions must be run on a Mac running macOS Big Sur Public Beta. If you are running an earlier version of macOS and have the Big Sur Public Beta installer, the drive cannot be created.
Macworld also has startup installation instructions for:
Get an external drive and maybe an adapter
MacOS Big Sur installation software is over 12 GB, so you need an external USB drive that can hold as much data. The drive can be a thumb drive, hard drive or SSD.
If you have a 2015 or newer Mac laptop that has USB-C / Thunderbolt 3 ports, you may need Apple’s $ 19 USB to USB-C adapter. This allows you to connect a storage device that uses a USB Type A connector. If you do not have an external drive and have a USB-C Mac laptop, you can purchase the SanDisk Ultra USB Type-C Flash Drive, which has a USB-C connector. You can get model number SDCZ450-016G-G46.
You need to delete the drive and format it to Mac OS Extended (Journaled). You can do this in the Mac’s Disk Utility app, which is in the Tools folder.
Get the MacOS Big Sur installation software
Big Sur is only available through Apple’s public beta program. You can sign up for the program, but keep in mind that this is beta software, so you may encounter issues. We suggest you try the beta version on a secondary Mac.
When you register, you will download and run the “macOS Public Beta Access Utility”, which will register your Mac in the program. Then the tool will launch Software Update to download and install Big Sur beta.
But after downloading when the installer starts, do not click the Continue button. Exit the installer by pressing Command-Q. Then go to your application folder and you will find an “Install macOS Big Sur Beta” app. You must have the app there to create the bootable drive.
For Macs that already have Big Sur beta installed and you do not have the installer in the Apps folder, you can download the installer by going to the “Register your devices” section of the Apple Beta Program website. Scroll down to step 2 and click the “Download macOS Public Beta access utility” button. Run the tool and exit the installer when it starts. You should find the installer in the Applications folder.
Use the terminal to create a bootable MacOS Big Sur installation drive
You will use the terminal to make the remote drive a bootable macOS Big Sur installer. Do not worry if you have never used Terminal before, it’s easy. Here are the instructions.
1. Connect the external drive to your Mac. In these instructions I use
Untitled as the name of the remote drive. If your drive is called something else, you need to change it
Untitled to the name of your station.
2. Launch the terminal (/Applications/Utilities/Terminal.app).
3. Select and copy the following:
sudo /Applications/Install macOS Big Sur Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled -- /Applications/Install macOS Big Sur Beta.app
4. Return to Terminal and paste the copied code when prompted. Remember to change
Untitled to the name of your station. Press Return.
5. Terminal can ask for your password. Enter it and press Enter.
6. Terminal will warn you that the external drive must be deleted. To continue, type Y at the command prompt and press Enter.
6. You see that Terminal deletes the drive and then copies the installation file to the drive. This will take a few minutes.
7. After copying, the Terminal is finished. You should see Terminal display a message stating that the drive is ready for use.
How to boot from the installation station
1. Connect the external drive to your Mac.
2. Turn on (or restart) your Mac. Press the Option key while the Mac starts up.
After a few moments, your Mac should display the Startup Manager, which will show you the available boot stations. Click on the remote drive and press Enter. (You do not have to select a network to continue.)
4. As part of the recovery process, you must select a user and enter a password.
5. Your Mac displays a MacOS Utilites window. To install Big Sur and leave the data intact, select Install macOS. To restart and delete the data, go to Disk Utility to format the internal drive first, and then install macOS Big Sur.
What should I do when ‘this copy of the OS X application cannot be verified’ or ‘installer payload failed in signature check’
Create a bootable installation station: Other ways
With earlier versions of macOS, I used a free app called Install Disk Creator to create the installation drive. I have also used DiskMaker X. These apps have not yet been updated to support Big Sur.
Since Big Sur is in beta, the developers of these two apps have probably not had the opportunity to create updated software. We check the two apps as the official Big Sur release approaches, and update this article as needed.