If your Mac isn’t running as smoothly anymore, you may decide to install an older, less demanding version of the macOS operating system. In principle, this is not a complicated process, but you do need to know where to find those older versions.
Have a backup
It’s good to know in advance that not all versions of macOS work on all devices. For example, you cannot install a version older than Big Sur on a Mac with Apple’s own M1 chip. Usually, a Mac only supports the operating system that was already on the device when you bought it, or newer versions of it that came out later. With a tool like Patched Sur you can always install new versions of macOS, even if your device basically doesn’t support them on its own. Often this is not recommended, as your Mac will not pull this.
In any case, make sure you make enough backups so that you can always restore your PC. Also keep in mind that it’s not always possible to restore backups you make with Time Machine to an older version of macOS. For example, it has been found that backups made in Big Sur are not so easy to restore in macOS Catalina from 2019. You can use another backup service or manually transfer your most important files to a hard drive that you have created yourself. then put it back on your new system.
Download old versions
You can download most older versions of macOS from the Mac App Store, but often you won’t find it if you search for it. That is why we have listed direct links to the different versions of the operating system:
macOS Big Sur (2020)
macOS Catalina (2019)
macOS Mojave (2018)
macOS High Sierra (2017)
Once you have downloaded the installer, do not proceed with the installation yet.
Also download OS X El Capitan. Safari downloads this older installer as a disk image named InstallMacOSX.dmg. Open the disk image and run the installer listed there under the name InstallMacOSX.pkg. This will install an app called OS X El Capitan–installation in the map apps and from this app you are going to install the older version of macOS.
Install old versions
To install an older version of macOS, you must first create a startup disk in order to install the operating system from an external drive. Apple recommends using a USB stick with at least 14GB of available space.
Plug the USB stick into your computer and open Disk Utility. below External you see the stick. Click at the top To clear and choose APFS (if you are installing macOS Sierra or later) or macOS Extended (if you install El Capitan or earlier versions). Give the stick a new name, for example MyVolume, and click To clear.
The easiest way is to use Terminal to create a startup disk. In Terminal you can create the startup disk with a single command, although it differs per macOS version which command you should use.
In this case, we assume that you want to install Big Sur. The command then looks like this:
sudo /Applications/Install macOS Big Sur.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume
We also assume that the installer is still in the folder apps state and that MyVolume is the name of the USB stick. If you did give the stick a different name, replace MyVolume in these commands by the name of your stick.
You can customize the command based on which version of macOS you want to install. If you want to install High Sierra, the command will rather be as follows:
sudo /Applications/Install macOS High Sierra.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume
After typing the command, press Enter and enter your password. Then confirm that you are going to overwrite your stick.
Now you can actually install macOS. This process may vary slightly from Mac to Mac. First make sure your computer is turned off. If you have a Mac with Apple’s M1 chip, insert the startup disk, i.e. your USB stick, into the Mac and turn on the Mac while holding down the power button until you see the startup options window . Select the startup disk here and you can start the installation process.
On a Mac with an Intel processor, you go through the same steps, but instead of the power button, you hold down the Option (Alt) key during startup. Then choose the startup disk and then click the up arrow or Enter.
This way you can install an older macOS version.
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