Every year Apple releases a major update to macOS, introducing new features and improvements for your Mac. These updates are totally free and you can even sign up to the public beta to access them early.
If you have a few Mac computers in your household or office, you probably don’t want to spend hours downloading the large macOS installation file multiple times. But Apple doesn’t save the macOS installer in an obvious location, so it’s difficult to use the same file again.
Worry not; we’ll show you how to make better use of the macOS installer.
Why Should I Save the macOS Installer?
Since most people only need to use it once, the macOS installer automatically deletes itself after you use it. This happens unless you save the installer before running the update.
Unlike most minor updates, the macOS installer includes an entire operating system for your Mac. That means it can be huge, sometimes as big as 8GB or more.
If you want to use the macOS installer multiple times, and you don’t save it first, you need to download it again on each Mac you update. This takes a long time to do and sucks up your internet bandwidth in the process, as each download could take two hours or more.
This could be a problem if there are lots of Mac computers in your home or office.
To make matters even worse, if you download the latest macOS update as soon as Apple makes it available, download times are likely to be even slower while Apple’s servers struggle to keep up with initial demand.
You can save yourself a lot of hassle by saving the macOS installer after downloading it the first time. That way, you can use the same macOS installer to update as many Mac computers as you need without multiple downloads.
You can even use the installer to install macOS on a Windows PC.
Save the macOS Installer to Create a Bootable USB
The macOS installer file may also be helpful if something goes wrong with your Mac in the future. If you decide to “start fresh” and reinstall macOS, you’ll need the macOS installer to do so.
If you want to keep the macOS installer for these troubleshooting reasons, it’s best to grab a spare flash drive and turn it into a bootable USB instead. This way, you can use the bootable USB to reinstall macOS even if your Mac doesn’t start up anymore.
To create a bootable USB installer, you need to boot your Mac into Recovery mode and use a special Terminal command. This is more complicated than if you only want to update several Macs—rather than repair them—so we’ll stick to the simple workflow below.
Remember: If you have an older Mac that doesn’t support the latest version of macOS, you should save the relevant macOS installer for that Mac in case you need to repair it in the future. You can download this file and create a bootable USB on any other Mac.
How to Download the macOS Installer
Although you can download the latest version of macOS from the System Preferences on your Mac, doing so also starts the installation process, which then deletes the installer.
It’s better to download the macOS installer from the Mac App Store instead. However, you still need to quit the macOS installer when it starts up after the download completes.
You can find the latest version of the macOS installer by searching for it in the Mac App Store. Although older versions of the macOS installer are also located on the App Store, they don’t turn up from a normal search.
Use these links to locate the relevant macOS installer on the Mac App Store instead:
- macOS Catalina
- macOS Mojave (no longer available)
- macOS High Sierra (no longer available)
Download the macOS installer as you would any other app: click Get, enter your Apple ID password, and wait for the download to complete. The installer launches automatically, so press Cmd + Q or go to Install macOS > Quit from the menu bar to close it.
Older versions of Mac OS X are not available on the Mac App Store anymore. But you can still download them as disk images directly from Apple’s website. After doing so, open the disk image to find the Mac OS X installers:
Where Is the macOS Installer Located?
Unlike most files, the macOS installer isn’t located in the Downloads folder after you download it. Instead, you’ll find the macOS installer located in your Applications folder.
The only exception is if you download OS X El Capitan or OS X Yosemite, which saves a disk image in your Downloads folder. Double-click to mount the disk image to find the OS X installer inside.
How to Save the macOS Installer
The macOS installer deletes itself after you run it, so you need to save a copy first. It’s best to keep this copy on an external drive so you can move it to other computers to keep installing macOS from the same file.
To copy it, control-click the macOS installer in your Applications folder and select Copy. Then open the destination drive or folder and control-click to Paste.
When you want to run the macOS installer to update a Mac, it’s best to create another copy of the installer file in the Applications folder on that Mac. Your Mac will delete this copy once the macOS installation finishes.
Before You Install macOS
Installing a new operating system is a major upgrade, and though most installations go smoothly, there’s always the chance that something could go wrong. For this reason, you should always back up your Mac with Time Machine before you update macOS.
There are also other precautions you can take before installing macOS to minimize the chance of problems:
- Open Disk Utility and run First Aid on your startup disk to clear out any permissions errors.
- Open the Apple menu and select About This Mac > Storage to make sure you have at least 16GB of free space to install the update.
- Make sure your MacBook is connected to power or fully charged before getting started.
The whole installation process usually takes around 30 minutes. You won’t be able to use your Mac during this time until it restarts at the end.
If you come across any problems, take a look at our troubleshooting guide for macOS installation errors.
Update Your Apps After Installing macOS
After updating macOS, open the Mac App Store to check for new updates for any of your apps. You need to update any apps you installed from outside the App Store separately, although most of them tell you when an update is available automatically.
You should also connect your Time Machine drive and create a new backup.
You might find that the latest version of macOS isn’t compatible with all your favorite apps. This happens from time to time. If you need to find replacement apps, take a look at our list of the best Mac apps to get started.
Looking for the best apps for your MacBook or iMac? Here’s our comprehensive list of the best apps for macOS.
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