Jul 28, 2014 The traditional method of creating a bootable OS X USB installer no longer works, so you’ll need to follow a new approach when dealing with OS X Yosemite. While there are multiple methods that will work, here’s the easiest way to create a bootable OS X 10.10 Yosemite USB Installer for the Yosemite Public Beta. Bootable USB Installers for OS X Mavericks, Yosemite, El Capitan, and Sierra. First, review this introductory article: Create a bootable installer for macOS.Second, see this How To outline for creating a bootable El Capitan installer.
These advanced steps are primarily for system administrators and others who are familiar with the command line. You don't need a bootable installer to upgrade macOS or reinstall macOS, but it can be useful when you want to install on multiple computers without downloading the installer each time.
What you need to create a bootable installer
- A USB flash drive or other secondary volume formatted as Mac OS Extended, with at least 14GB of available storage
- A downloaded installer for macOS Big Sur, Catalina, Mojave, High Sierra, or El Capitan
Download macOS
- Download: macOS Big Sur, macOS Catalina, macOS Mojave, or macOS High Sierra
These download to your Applications folder as an app named Install macOS [version name]. If the installer opens after downloading, quit it without continuing installation. To get the correct installer, download from a Mac that is using macOS Sierra 10.12.5 or later, or El Capitan 10.11.6. Enterprise administrators, please download from Apple, not a locally hosted software-update server. - Download: OS X El Capitan
This downloads as a disk image named InstallMacOSX.dmg. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. You will create the bootable installer from this app, not from the disk image or .pkg installer.
Use the 'createinstallmedia' command in Terminal
- Connect the USB flash drive or other volume that you're using for the bootable installer.
- Open Terminal, which is in the Utilities folder of your Applications folder.
- Type or paste one of the following commands in Terminal. These assume that the installer is in your Applications folder, and MyVolume is the name of the USB flash drive or other volume you're using. If it has a different name, replace
MyVolume
in these commands with the name of your volume.
Big Sur:*
Catalina:*
Mojave:*
High Sierra:*
El Capitan:
* If your Mac is using macOS Sierra or earlier, include the --applicationpath
argument and installer path, similar to the way this is done in the command for El Capitan.
After typing the command:
- Press Return to enter the command.
- When prompted, type your administrator password and press Return again. Terminal doesn't show any characters as you type your password.
- When prompted, type
Y
to confirm that you want to erase the volume, then press Return. Terminal shows the progress as the volume is erased. - After the volume is erased, you may see an alert that Terminal would like to access files on a removable volume. Click OK to allow the copy to proceed.
- When Terminal says that it's done, the volume will have the same name as the installer you downloaded, such as Install macOS Big Sur. You can now quit Terminal and eject the volume.
Use the bootable installer
Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
Apple silicon
- Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
- Turn on your Mac and continue to hold the power button until you see the startup options window, which shows your bootable volumes.
- Select the volume containing the bootable installer, then click Continue.
- When the macOS installer opens, follow the onscreen instructions.
Intel processor
- Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing.
- Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac.
- Release the Option key when you see a dark screen showing your bootable volumes.
- Select the volume containing the bootable installer. Then click the up arrow or press Return.
If you can't start up from the bootable installer, make sure that the External Boot setting in Startup Security Utility is set to allow booting from external media. - Choose your language, if prompted.
- Select Install macOS (or Install OS X) from the Utilities window, then click Continue and follow the onscreen instructions.
Learn more
A bootable installer doesn't download macOS from the internet, but it does require an internet connection to get firmware and other information specific to the Mac model.
For information about the createinstallmedia
command and the arguments you can use with it, make sure that the macOS installer is in your Applications folder, then enter the appropriate path in Terminal:
By Michael Argentini
Managing Partner, Technology and Design
How do you erase your Mac hard drive and install OS X Yosemite without a startup disk? Normally the answer would be to boot into recovery mode. But what if you need to partition the hard drive, wiping the recovery partition? You need a bootable OS X Yosemite installer. Here's how to make one using Apple's built-in boot drive creation tool.
What You Need
- The 5GB OS X Yosemite installer app that downloads into your Applications folder when you first install it via the Mac App Store. The file name is Install OS X Yosemite. After you upgrade to Yosemite, this file is deleted. So you have to quit the installer once it appears in order to keep this file.
- A flash drive, external hard disk, SD card, or the like, with at least 8GB of capacity.
- Your Mac user account must be an Administrator. If it isn't, go to Users & Groups in System Preferences and assign Administrator to your user account. You can change it back to a standard user when you're finished. You can also sign in to your Mac as the administrator to create the bootable drive.
Step 1: Format Your Drive
First, you must partition and erase the drive so that it can be bootable. To do this, launch Disk Utility and choose the destination drive in the drive list (left column). On the right, in the Erase tab, choose to format the drive as Mac OS Extended (Journaled). These are the defaults, so just confirm the settings.
Next go to the Partition tab and under Partition Layout choose '1 Partition' in the dropdown menu. Change the name from 'Untitled 1' to 'Untitled'. This is so that the Terminal command below will find the drive. Once the process is complete, the drive name will be 'Install OS X Yosemite'.
Click the 'Options' button. In the dialog that appears, choose 'GUID Partition Table' as the partition scheme, then click 'OK'. Again, this is the default, so just confirm the setting.
Finally, click 'Apply' to confirm the settings and prepare the drive.
Step 2: Make the Drive a Yosemite Boot Installer
In a single command you'll create the bootable install drive. Pretty sweet! To do this, launch Terminal and enter the following command. Note, this assumes that you haven't moved the installer out of your Applications folder. If you have, simply replace '/Applications' with the location of the installer:
Macos Yosemite Usb Installer Downloads
The sudo command will ask for your password. As you type it will not appear. This is normal. Just enter it and press return to create the boot drive.
Make Yosemite Bootable Usb
During installation, you'll see a progression of status messages.
Wait until you see a status of 'Done.' When you do, you can safely eject the drive and quit Terminal.
Step 3: Start Up from the Install Drive
If you open the new bootable drive in the Finder, you'll notice that it appears empty, other than the Install OS X Yosemite app. No worries. The boot files are hidden, and the installer app allows you to upgrade without booting from the drive if you don't need to.
To boot from this new installer, shut down the Mac, plug in the bootable drive, and hold down the option key while powering back up. You should eventually see a series of bootable drives. Click on the one named 'Install OS X Yosemite' and press the return key.