Create a bootable USB stick with Apple Mac OS X also for downgrading
Today I will describe to you how you can create a bootable USB stick for emergencies or for upgrading or downgrading an existing Mac OS X operating system.
Contrary to some statements that can be found on the net, it is currently possible to downgrade the operating system again, i.e. to install an earlier operating system.
If your iMac , MacBook Pro or Mac Mini / Pro was released in 2013 and the first devices were released with OS X Mavericks 10.9, for example, you can downgrade the device to this operating system if it has been updated.
It is not possible to install an operating system that was released before the release date of your device.
Here are some release dates for Apple operating systems:
Mac OS X Snow Leopard 10.6 - 08/28/2009
Mac OS X Lion 10.7 - 11/20/2011
Mac OS X Mountain Lion 10.8 - 11/25/2012
Mac OS X Mavericks 10.9 - 10/22/2013
Mac OS X Yosemite 10.10 - 10/16/2014
Mac OS X El Capitan 10.11 - 09/30/2015
Mac OS X Sierra 10.12 - 09/20/2016
Mac OS X High Sierra 10.13 - 09/25/2017
Mac OS X Mojave 10.14 - 09/24/2018
Mac OS X Catalina 10.15 - 10/07/2019
Mac OS X Big Sur 11.0 - 11/12/2020
Mac OS X Monterey 12.0 - 10/25/2021
There are two ways to create a bootable stick:
1. The integrated Apple tool that is started via the terminal.
2. Free software such as DiskMaker for Mac OS X.
Creating the USB stick
First we need the image for the operating system, i.e. a file that contains the software.
I would only ever advise images directly from Apple, since other sites may have integrated malware.
Here are some images for the operating systems directly from Apple:
Monterey: Directly on the App Store
Only download the required image but do not install it. Once the download is complete, the stick can be created.
To create a stick, an 8GB USB stick is required for older operating systems up to Mojave. For Catalina it should be a bigger stick 16GB.
First, the stick must be erased.
To do this, open the disk utility (click on the magnifying glass in the upper right corner and search for and select disk utility).
Select and delete the stick in Disk Utility and assign a name (Mac OS Extended /Guide partition table).
I call the stick "empty" here.
Once the stick is erased, close Disk Utility.
If you create the stick using software such as Diskimage, you can skip the following steps and simply start your software.
This description refers to the integrated Apple tool for creating a boot stick.
Open the terminal (click on the magnifying glass at the top right and search for terminal and confirm).
Here are the terminal commands for the different operating systems:
sudo /Applications/Install\ macOS\ Monterey.app/Contents/Resources/createinstallmedia --volume /Volumes/ empty
sudo /Applications/Install\ macOS\ Big\ Sur.app/Contents/Resources/createinstallmedia --volume /Volumes/ empty
sudo /Applications/Install\ macOS\ Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/empty
sudo /Applications/Install\ macOS\ mojave.app/Contents/Resources/createinstallmedia --volume /Volumes/empty
High Sierras :
sudo /Applications/Install\ macOS\ High\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/empty
sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/empty
El Capitan :
sudo /Applications/Install\ macOS\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/empty
The command can simply be copied and pasted into the terminal. If you have also named your stick empty , you only have to press the Enter key. If you have named your stick differently, the blank must be replaced with the name you assigned.
Now you have to enter your administrator password, which you use in Mac OS X, for confirmation and then confirm with the Y key.
Now the stick is created. Terminal reports when the stick is ready.
In order to install the operating system via the stick, it must logically be connected to the device. If the device is not already switched off, switch off the device.
To start from the stick, the left ALT (option) key must be pressed and held until the stick appears on the display (Install Mac OS...).
Then select and start the stick.
Then select the desired language.
If you want a complete new installation (clean install, without all your data) or a downgrade/older operating system, the hard drive must first be erased. With a simple update, if you want to keep your data, this is not necessary . Here you can go directly to install macOS and confirm the further steps.
Description Downgrade/Clean Install (Attention all data will be deleted)
Select Disk Utility from the menu.
In Disk Utility, click on "View " in the top left corner and set it to "Show all devices" .
Select the hard drive/SSD - not the partitions!
Then click Delete and give the hard drive a name. Then confirm everything.
Once the hard drive is erased, exit Disk Utility.
Now the operating system can be reinstalled. To do this, go to "Install macOS" and continue.
Confirm all further steps with Continue and select the hard disk on which the operating system is to be installed.
Finally confirm the installation.
The whole thing is also described here directly by Apple, if anything is unclear:
Attention very important! Always connect the unit to an AC adapter/power supply during installation. Always wait for the installation to complete. Some operating systems like High Sierra, Mojave or Catalina will also reinstall the firmware. In some cases, the screen goes completely black for several seconds or even minutes, which can lead to the incorrect assumption that the installation has failed and the device then switches off or restarts. Never switch off or restart the device, otherwise the firmware may be damaged and the device will no longer start at all. If your screen goes black, wait at least 30 minutes before you do anything.
Attention, we assume no liability for any errors that arise! You act on your own responsibility, so installations should only be carried out by experienced users.