1. Launch Disk Utility (press Command + spacebar and start to type Disk Utility). Before this next step, note: if you are running High Sierra or later you will need to click on the View drop down.
2. Today I am showing how to make a boot able USB drive for Mac Using a.dmg file, 8gb usb drive, and the Disk Utility that comes with Mac OS X. I hope this hel.
3. Select Mac OS X Install ESD in Disk Utility’s sidebar, then click the Restore button in the main part of the window. Drag the Mac OS X Install ESD icon into the Source field on the right (if it.

Starting up Mac OS into Recovery Mode allows for various important troubleshooting and recovery features, including the ability to reinstall MacOS, repair a hard drive with Disk Utility, erase a boot disk, restore a Mac from a Time Machine backup, adjusting and setting Firmware passwords, as well as some other more advanced functionalities. Select your disk in Disk Utility Choose View Show All Devices (if available) from the menu bar or toolbar in Disk Utility. The sidebar in Disk Utility should now show each available disk or other storage device, beginning with your startup disk. And beneath each disk you should see any containers and volumes on that disk.

• Supported version: 0.6.5

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 gibMacOS.

# 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 gibMacOS utility.

Now let's grab gibMacOS(opens new window), then unzip it into a local directory.

Next run the gibMacOS.command:

As you can see, we get a nice list of macOS installers. If you need beta versions of macOS, you can select C. Change Catalog. For this example we'll choose 1:

• 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, we have to either extract the installer or build it:

• Extracting the installer
  • For macOS 11+
• Building the installer
  • For 10.15 and older

# Extracting the installer

For macOS 11 and newer, Apple now packages up the installer into the InstallAssistant package. This will be located under gibMacOS/macOS Downloads/:

Run the InstallAssistant.pkg and point this to whichever drive you're booting off of, this is where the Install.app will be dropped:

Once done, you should find it located in your Applications folder:

From here, jump to Setting up the installer to finish your work.

# Building the installer

Osx Usb Boot Disk Utility

For macOS 10.15 and older, the installer will be downloaded in pieces and will need to be built. Here we'll want to run the BuildmacOSInstallApp.command:

You will be prompted for the macOS installer files which were downloaded to macOS Downloads folder in the gibMacOS directory.

From the Finder, drill down to the folder containing the downloaded files and either drag it to the command line or 'Cmd+C' and paste it to the terminal.

Once the task is completed, exit the utility. You will find the Install file in the directory.

Move the newly created image to the Applications folder – this will simplify the next section.

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)

Bootable Disk Utility Mac

# Legacy macOS: Offline method

This method allows us to download full installers from Apple, however is limited to 10.10, Yosemite, so older OSes will need to be grabbed via the 'Online Method' mentioned below.

To start, go to the following link:

Download your desired version and a .pkg file should be provided.

Depending on what OS you're on, you can run this script and head to Setting up the installer however if you receive this error:

This means we'll need to manually extract the installer.

# Extracting the Installer

To start, grab the InstallMacOSX/InstallOS.dmg and mount it:

Next, let's open up terminal window and make a folder on our desktop to break things. Run one at a time:

Now we get to the fun part, extracting the installer(Note this may take a few minutes):

• For El Capitan(10.11) and older:

• For Sierra(10.12):

Next, run the following(one at a time):

• Yosemite:

• El Capitan:

• Sierra:

Once this is done, you can head to Setting up the installer!

# Legacy macOS: Online method

This method allows us to download legacy versions of macOS including 10.7 to current, however these are only recovery installers so require an internet connection inside the installer itself

To start, you'll want to use macrecovery.py instead. This tool is actually already bundled in OpenCorePkg:

Instructions for running are quite simple, choose from one of the below commands depending on which OS you want to download:

From here, run one of those commands in terminal and once finished you'll get an output similar to this:

Once this is done, format your USB as FAT32 with GUID Partition Scheme:

And finally, create folder on the root of this drive called com.apple.recovery.boot and place the newly downloaded BaseSystem/RecoveryImage files in:

From here, you can skip to Setting up OpenCore's EFI environment

# Legacy macOS: Disk Images

This method instead relies on hosted images either from Apple or Acidanthera, and restoring onto your drive.

# Acidanthera Images

The below installers were pulled from genuine Mac restore disks with their SMBIOS lock removed, contents of OS X itself have not been modified in any way.

# Apple Images

Note that these images require you to have an Apple Developer account to access.

# Restoring the drive

Now comes the fun part, you'll first want to open the dmg you just downloaded and have it mounted. Now open Disk Utility and format your drive as macOS Extended(HFS+) with a GUID partition map:

Next we have 2 options to follow:

• ASR Restore(Apple Software Restore)
  • Terminal based, works with SIP enabled
• Disk Utility Restore
  • May require SIP disabled in newer OSes

# ASR

Here you'll simply want to open terminal and run the following:

• Note: This may not align with your setup, please change accordingly:
  • Change /Volumes/Mac OS X Install DVD to what your mounted Disk Image is called
  • Change /Volumes/MyVolume to what your USB is called

This will take some time but once you're finished, you can skip to Setting up OpenCore's EFI environment

# Disk Utility

Due to some pesky issues with Disk Utility, many restores can fail if SIP is enabled. If you have issues we recommend either using the ASR Method or disable SIP.

To start, open Disk Utility and you should see both your USB drive and the Disk Image in the sidebar. From here, select restore

This will take some time but once you're finished, you can skip to Setting up OpenCore's EFI environment

If you get an error such as this one during restore:

This likely means SIP needs to be disabled, however we recommend using ASR Method instead.

# 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/
• 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

Here is a guide on how to create a bootable external Mac hard drive to run macOS from an external hard drive.

There are quite a few reasons for why you may want to be able to have an additional startup drive for your Mac. One of the main reasons is backup of your current system. Another is creating a drive for testing your Mac’s hardware. No matter the reason, having an additional bootable option on an external hard drive is definitely a good tool for any Mac user to have.

How to Make a Bootable External Mac Hard Drive

Here are the steps to create a bootable external volume to start up to on your Mac.

How to Create a Second Boot Volume

In order to create another boot volume for your Mac, you will need a form of external storage such as a hard drive. The faster the drive the better and a connection speed like Thunderbolt is preferred. You are going to be utilizing this hard drive, Disk Utility and MaOS installer from the App Store.

If you are running the newest version of Sierra, you will be able to use the Recovery Boot option to launch your installation of MacOS to install it on your external drive. In order to boot to Recovery, restart holding Command and R. You will then choose Reinstall a new copy of MacOS to begin the next step.

If your secondary hard drive was just purchased, you may need to open Disk Utility prior to starting your installation. You will want to ensure that your hard drive is in the proper partition scheme and is available to install to. Many drives purchased from third party retailers may come unformatted or formatted to Windows based schemes like NTFS and FAT32. In Disk Utility you will want to make sure it is set to Mac OS Extended (Journaled).

Upon starting the Install feature of Recovery, you will be presented with the option of choosing which Disk the installer is going to do its work on. You should see your current Macintosh HD and also your external hard drive. Choosing this as your install target should begin the installation process and install MacOS Sierra on your external hard drive. When the machine reboots, it will be booting to your external hard drive where you can set up an account and get to your desktop.

How to Use Your Bootable Mac Disk

Now that you have created a second bootable drive, you are able to plug it in and reboot to it at any point in time. When you wish to do this, plug in the drive and reboot your Mac holding the Option key. Much like you did when installing, you will see your Macintosh HD and your now bootable External Drive show up as options. Clicking the External will start your Mac up on this new volume.

If you have completed the setup process and have an account enabled, the Mac will perform almost identically to how it would using the built-in drive. You are able to install applications on this drive and store media and information as backup or just additional copies. Many users will actually utilize a second hard drive option strictly for work related activities and then use the built-in drive for personal use.

This method is a safe way to keep a second bootable machine safely on a hard drive in the event of your internal hard drive crashing. You will also be able to test if it is indeed an issue with your hard drive by attempting to boot to your second drive and see if you can reproduce your issue.

Having a secondary boot volume has always been a personal recommendation as it comes in handy when you need a secondary place to separate data or use as a recovery tool in the event of mishaps.

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