Yes you can still do this –
You’ll just need one USB flash drive to install Catalina on a bunch of Macs.
Enlarge/Making a USB install drive for macOS Catalina is as easy as ever, if it’s something you need.
Andrew Cunningham
Apple hasn’t shipped operating systems on physical mediain a full decade, but there are still good reasons to want a reliable old USB stick for macOS Catalina . Luckily, it’s not hard to make one — either with a handy graphical user interface or some light Terminal use. Here’s what you need to get started:
- A Mac that you have administrator access to. We’ve created a USB stick from both Mojave and Catalina, but your experience with other versions may vary.
- A (GB or larger USB flash drive or a) GB or larger partition on some other kind of external drive. A USB 3.0 drive will make things significantly faster, but an older USB 2.0 drive will work in a pinch; 8GB drives worked for Mojave and older versions of macOS, but the Catalina installer is just a little too large to fit.
- The macOS 10. 15 Catalina installer from the Mac App Store (in High Sierra or older macOS versions) or the Software Update preference pane in Mojave. The installer will delete itself when you install the operating system, but it can be re-downloaded if necessary.
- If you want a GUI, take a look atBen Slaney’s Install Disk Creator from MacDaddy. There are other apps out there that do this, but this one is quick and simple.
If you want to use this USB installer with newer Macs as they are released, you’ll want to periodically re-download new Catalina installers and make new install drives. Apple rolls support for newer hardware into new macOS point releases as they come out, so this will help keep your install drive as universal and versatile as possible.
There’s also one new consideration for newer Macs withApple’s T2 controller chip– as of this writing, that list includes the iMac Pro, the 2018 Mac Mini, the 2018 MacBook Air, and 2018 and 2019 MacBook Pros, though Apple keeps an updated listhere. Among this chip’s many security features is one that disallows booting from external drives by default. To re-enable this feature, hold down Command-R while your Mac reboots to go into Recovery Mode and use theStartup Security Utilityto “allow booting from external media.” If you’re trying to install an older version of macOS, you may also need to go from Full Security to Medium Security to enable booting, but if you’re just trying to install the current version of macOS, the Full Security option should be just fine. And if you’re just doing an upgrade install rather than a clean install, you can run the Catalina installer from the USB drive from within your current installation of macOS, no advanced tweaking required.
The easy way
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Install Disk Creator puts a friendly face on the normal terminal command.
Andrew Cunningham
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Select the macOS installer you’d like to use; the tool can work with the High Sierra, Mojave, and Catalina installers (and probably others, though we haven’t tested anything else with the latest version).
Andrew Cunningham
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You’ll need a flash drive or external volume with 16 GB or more of space, which will be formatted before it’s used.
Andrew Cunningham
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Put in your password and you’re off to the races.
Andrew Cunningham
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The time it takes to create your disk will depend on the kind of USB stick you’re using.
Andrew Cunningham
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And you’re done!
Once you’ve obtained all of the necessary materials, connect the USB drive to your Mac and launch the Install Disk Creator. This app is basically just a GUI wrapper for the terminal command, so it should be possible to make install disks for versions of macOS going all the way back to Lion. In any case, it will work just fine for our purposes.
Install Disk Creator will automatically detect macOS installers on your drive and suggest one for you, displaying its icon along with its path. You can navigate to a different installer if you want, and you can also pick from all the storage devices and volumes currently connected to your Mac through the drop-down menu at the top of the window. Once you’re ready to go, click “Create Installer” and wait. A progress bar across the bottom of the app will tell you how far you have to go, and a pop-up notification will let you know when the process is done. This should only take a few minutes on a USB 3.0 flash drive in a modern Mac, though using USB 2.0 will slow things down.
The only slightly less-easy way
The Install Disk Creator is just a wrapper for the terminal command to create macOS install disks, so if you’re comfortable formatting your USB drive yourself and opening a Terminal window, it’s almost as easy to do it this way. Assuming that you have the macOS Catalina installer in your Applications folder and you have a Mac OS Extended (Journaled) -formatted USB drive (which is to say, HFS andnotAPFS) named “Untitled” mounted on the system, you can create a Catalina install drive using the following command.
sudo / Applications / Install macOS Catalina.app/Contents/Resources/ createinstallmedia --volume / Volumes / Untitled
The command will erase the disk and copy the install files over. Give it some time, and your volume will soon be loaded up with not just the macOS installer but alsoan external recovery partitionthat may come in handy if your hard drive dies and you’re away from an Internet connection. If you would like to create an install drive for a macOS version other than Catalina, just tweak the paths above to refer to Mojave or High Sierra instead.
Whichever method you use, you should be able to boot from your new USB drive either by changing the default Startup Disk in System Preferences or by holding down the Option key at boot and selecting the drive. Once booted, you’ll be able to install or upgrade Catalina as you normally would. You can also use Safari, Disk Utility, or Time Machine from the recovery partition to restore backups or troubleshoot.
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