The Catalina installer app will be in your Applications folder, so you can go there and launch it later to upgrade your Mac to the new operating system. Make a bootable installer drive: The quick way. If the installer needs more storage space to upgrade, you can free up space using tools that come with your Mac. Free up storage space. Download macOS Big Sur.
- Supported version: 0.6.7
While you don't need a fresh install of macOS to use OpenCore, some users prefer having a fresh slate with their boot manager upgrades.
To start we'll want to grab ourselves a copy of macOS. You can skip this and head to formatting the USB if you're just making a bootable OpenCore stick and not an installer. For everyone else, you can either download macOS from the App Store or with Munki's script.
# Downloading macOS: Modern OS
- This method allows you to download macOS 10.13 and newer, for 10.12 and older see Downloading macOS: Legacy OS
From a macOS machine that meets the requirements of the OS version you want to install, go directly to the App Store and download the desired OS release and continue to Setting up the installer.
For machines that need a specific OS release or can't download from the App Store, you can use the Munki's InstallInstallMacOS utility.
In order to run it, just copy and paste the below command in a terminal window:
As you can see, we get a nice list of macOS installers. If you need a particular versions of macOS, you can select it by typing the number next to it. For this example we'll choose 10:
- macOS 11, Big Sur Note: As this OS is quite new, there's still some issues with certain systems to resolve. For more information, see here: OpenCore and macOS 11: Big Sur
- For first time users, we recommend macOS 10.15, Catalina
- Nvidia GPU Note: Reminder to verify whether your hardware support newer OSes, see Hardware Limitations
This is going to take a while as we're downloading the entire 8GB+ macOS installer, so it's highly recommended to read the rest of the guide while you wait.
Once finished, you'll find in your ~/macOS-Installer/ folder a DMG containing the macOS Installer, called Install_macOS_11.1-20C69.dmg for example. Mount it and you'll find the installer application.
- Note: We recommend to move the Install macOS.app into the
/Applicationsfolder, as we'll be executing commands from there. - Note 2: Running Cmd+Shift+G in Finder will allow you to easily jump to
~/macOS-installer
From here, jump to Setting up the installer to finish your work.
# Downloading macOS: Legacy OS
This method allows you to download much older versions of OS X, currently supporting all Intel versions of OS X(10.4 to current)
- Legacy macOS: Offline method
- 10.10-10.12 Supported
- Legacy macOS: Online method(10.7-10.15 Supported)
- 10.7-11 Supported
- Legacy macOS: Disk Images
- 10.4-10.6 Supported
- Legacy macOS: Offline method
# Setting up the installer
Now we'll be formatting the USB to prep for both the macOS installer and OpenCore. We'll want to use macOS Extended (HFS+) with a GUID partition map. This will create two partitions: the main MyVolume and a second called EFI which is used as a boot partition where your firmware will check for boot files.
- Note: By default, Disk Utility only shows partitions – press Cmd/Win+2 to show all devices (alternatively you can press the View button)
- Note 2: Users following 'Legacy macOS: Online method' section can skip to Setting up OpenCore's EFI environment
Next run the createinstallmedia command provided by Apple(opens new window). Note that the command is made for USB's formatted with the name MyVolume:
This will take some time so you may want to grab a coffee or continue reading the guide (to be fair you really shouldn't be following this guide step by step without reading the whole thing first).
You can also replace the createinstallmedia path with that of where your installer's located (same idea with the drive name).
Pulled from Apple's own site: How to create a bootable installer for macOS(opens new window)
# Legacy Setup
For systems not supporting UEFI boot, see below:
To start, you need the following:
- BootInstall_IA32.tool or BootInstall_X64.tool
- This can be found in OpenCorePkg under
/Utilties/LegacyBoot/
- This can be found in OpenCorePkg under
- Install USB(Created above)
Within your OpenCore build folder, navigate to Utilities/LegacyBoot. Here you'll find a file called BootInstall_ARCH.tool. What this does is install DuetPkg to your desired drive.
Now run this tool in terminal with sudo(This tool will likely fail otherwise):
This will give you a list of available disks, choose yours and you will be prompted to write a new MBR. Choose yes[y] and you'll be finished.
This will provide you with an EFI partition with either a bootia32 or bootx64 file
# Setting up OpenCore's EFI environment
Setting up OpenCore's EFI environment is simple – all you need to do is mount our EFI system partition. This is automatically made when we format with GUID but is unmounted by default, this is where our friend MountEFI(opens new window) comes in:
You'll notice that once we open the EFI partition, it's empty. This is where the fun begins.
# Now with all of this done, head to Setting up the EFI to finish up your work
Upgrade to macOS Big Sur
Before installing this upgrade, make sure that your Mac is ready.
Check compatibility
macOS Big Sur supports most Mac models introduced in 2013 and later.
View compatible Mac modelsMac Os Catalina Installer
Make a backup
Before you upgrade, make a complete backup with Time Machine, or store your files in iCloud.
Learn how to back up your MacFree up space
Mac Os Catalina Installer Apple
If the installer needs more storage space to upgrade, you can free up space using tools that come with your Mac.
Free up storage spaceDownload macOS Big Sur
If you’re using macOS Mojave or later, choose Apple menu > System Preferences, then click Software Update. If you’re using an earlier macOS, use the App Store instead.
Learn how to download and install macOS Big SurGo to the App StoreGet to know macOS Big Sur
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