Catalina Bootable Disk

Apple hasn’t shipped operating systems on physical media in 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:

Insert your USB flash drive (4Gb + preferable) into your system. Warning: All data on the USB flash drive will be lost, make sure you save any data before proceeding. Navigate to the Command Prompt. Select Start & type CMD in the search field, right click on CMD.exe and select Run as administrator. Step Three: Create macOS Catalina Bootable USB Installer in Windows on Terminal. The USB installer has now been formated, it’s time to create and copy the installer with a command on Terminal. For this purpose, open Spotlight and type Terminal. Select the “Install macOS Catalina” (with left/right arrow keys) and hit the “return/enter” key to boot from the USB flash drive. It may take 5-10 minutes to load the installer from the USB flash drive. Sometimes the progress bar may appear to be frozen or the screen will go black for a minute or two. Part 3: Create Bootable macOS Catalina USB Using DMG Editor. If you have download macOS Catalina DMG file, then UUByte DMG Editor is the only tool you can find to make a macOS bootable USB from DMG disk image. However, if you downlaoded the Catalina install app from App store, please skip this part and read the following recommendations. This article guides you through the process of performing a clean installation of macOS 10.15 Catalina using the bootable USB drive method, rather than upgrading your Mac using Apple's standard.

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 16GB or larger USB flash drive or a 16GB 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 at Ben 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 with Apple'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 list here. 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 the Startup Security Utility to '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

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.

Catalina Bootable Disk Manager

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+ and notAPFS) 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 also an external recovery partition that 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.

Apple has just released the latest update to macOS. The update, named macOS Catalina, brings a bucket-full of new features including the ability of using iPad as an external screen for Mac. It also officially kills the 20-year-old iTunes (on Mac) and brings separate apps to manage music and podcasts while also adding a new TV app.

Macos Catalina Boot Disk Usb

Other notable changes include the abandonment of 32-bit apps in favour of 64-bit apps, refreshed Reminders, Photos, Mail, Safari, and Notes apps, and the introduction of Apple Arcade among others.

Whether you should upgrade your Macs to the new macOS Catalina is entirely up to your current workflow. The change that could affect it the most is the support for 32-bit apps being officially dropped. If you rely on old apps that needs an update for the new platform, you might want to hold your upgrade until these apps are updated or you find alternatives.

With macOS Catalina, Apple has changed the way you used to download the installer. Previously, you would download the new OS installer from AppStore itself and then use that installer to make a bootable installer for later use. In Catalina, when you click the Get button in AppStore, you are taken to the Software Update screen to download the new update.

This change makes is a bit tricky to create a bootable install media like a USB stick or memory card. Albeit not as straightforward as before, but it is definitely possible to make a bootable installer for macOS Catalina. This tutorial shows how to do that.

Update – 12th November, 2020: The latest update to macOS is out now. Learn how to make a bootable macOS Big Sur installer.

Make a Bootable macOS USB Stick or Memory Card

Before you begin:

Make sure you have a USB stick aka pen drive aka flash drive or memory card aka SD card with at least 16GB of storage.
Take complete backup of data on your Mac.
Make sure you have a working, strong, and stable Wi-Fi connection to download macOS Catalina.

Step 1

Due to the way you get your copy of macOS Catalina has changed a bit, we will rely on a third-party app which will help us get the installer. The app we will use for this is called macOS Catalina Patcher which is primarily used to make a patched installer for old Macs that don’t support new versions of macOS.

Download macOS Catalina Patcher, place it under Applications, launch it, and click Continue. Click Download a Copy.

Make Bootable Catalina Disk

Now, before you move to the next screen, click Options in the menu bar and disable ‘Auto-apply Post Install Patches.’ After that, click Start Download and wait for the download — that is around 8GB — to finish.

Update: I just read other tutorials mentioning that you don’t need macOS Catalina Patcher. You can download macOS Catalina installer from the Software Update screen and it’s placed under Applications. If you wish to go ahead with that method, you can change the path in the Step 3 from Downloads to Applications.

Step 2

Once the download is finished, you can see ‘macOS Catalina Installer” under Downloads folder. Now it’s time to erase your USB stick or memory card.

Insert the medium you wish to use for creating a bootable installer in your Mac and open Disk Utility. Select the medium from the list on left and click Erase. Select Mac OS Extended (Journaled) under Format. Type Untitled in Name field (you can choose any name here).

How To Make A Bootable Catalina Drive

Click Erase and wait for the process to finish. Remember that you are completely erasing the data on this media.

Catalina Boot Disk Creator

Step 3

Now you are ready to move to the final step which is to create the bootable macOS Catalina media.

Open Terminal and type the following command. Make sure you don’t leave any spaces in-between.

sudo /Downloads/Install macOS Catalina.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled

Note: Replace Untitled (in bold above) with whichever name you gave in step 2.

If copying and pasting or typing this command doesn’t work, you can do the following.

Type sudo in Terminal and keep the window open. Now open Downloads folder and drag the macOS Catalina Installer file on the Terminal window. It will automatically generate the path where your Catalina installer is located.

Now, append --volume /Volumes/Untitled at the end of the automatically generated string and press Return key on keyboard. Note that there are two dashes (--) before volume and a space after volume.

Enter your password, press Y and press enter to start the process and let it finish — which will take about 15 minutes.

How to Install macOS Catalina from a Bootable Volume?

Once Terminal finishes the process, you can restart your Mac and when it is booting up, press and hold Option key until you see a black screen with an option to select the startup disk.

Select Install macOS Catalina and click continue. Let the installer load and once it’s finished, you should enter macOS Recovery screen which will ask you to select a user account which you know the password of. Choose your administrator account and enter its password.

Now click Disk Utility and continue. Select the volume where your current macOS is installed. The volume is usually named macOS. Click Erase. Leave the options as default and click Erase again.

After the process finishes, close Disk Utility and you will return to the recovery screen. This time, select Install macOS and continue.

Let the install process finish, which consists of a couple of automatic reboots. Once finished, you should see the initial macOS setup screen. After you are done with this on-boarding step, you will see the desktop and are all set to start using macOS Catalina on your Mac.

Making a Bootable macOS Installer Media: Summing Up

Bootable macOS installer is useful if you want to completely erase your Mac and reinstall the operating system, or if you have more than one Macs and you don’t want to spend time (and bandwidth) downloading the macOS update.

Making a bootable macOS Catalina installer isn’t too complicated. You can make a bootable flash drive aka pen drive aka USB stick or memory card and use it to install the latest macOS version on your Mac.

That’s it, folks. This was a quick tutorial on how to create a bootable macOS Catalina installer on a flash drive or memory card. I hope you found it useful.