You can use an external drive or secondary volume as a startup disk from which to install the Mac operating system. 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.
There are times when you may want to avoid using App Store or the built-in recovery mode to install OS X 10.10 Yosemite. So, Apple continues to give you the option of creating a bootable USB drive. Welcome Create Install Media OS X Yosemite Video Make sure Install OS X Yosemite.app is on Applications Folder You need USB 8 Gig or Ext USB Hard Drive Plug your USB Volumes to your machine; not.It was 2009 when Apple last released a new operating system on physical media. Things have proceeded remarkably smoothly since version 10.7 switched to download-only installers, but there are still good reasons to want an old, reliable USB stick. For instance, if you find yourself doing multiple installs, a USB drive may be faster than multiple downloads (especially if you use a USB 3.0 drive). Or maybe you need a recovery disk for older Macs that don't support the Internet Recovery feature. Whatever the reason, you're in luck, because it's not hard to make one.
As with last year, there are two ways to get it done. There's the super easy way with the graphical user interface and the only slightly less easy way that requires some light Terminal use. Here's what you need to get started.
- A Mac, duh. We've created Yosemite USB from both Mavericks and Yosemite, but your experience with other versions may vary.
- An 8GB or larger USB flash drive or an 8GB or larger partition on some other kind of external drive. For newer Macs, use a USB 3.0 drive—it makes things significantly faster.
- The OS X 10.10 Yosemite installer from the Mac App Store in your Applications folder. The installer will delete itself when you install the operating system, but it can be re-downloaded if necessary.
- If you want a GUI, you need the latest version of Diskmaker X app—we wrote this article based on version 4 beta 2, but if a 'final' version is released alongside Yosemite we'll update the article. This app is free to download, but the creator accepts donations if you want to support his efforts.
- An administrator account on the Mac you're using to create the disk.
The easy way
Once you've obtained all of the necessary materials, connect the USB drive to your Mac and run the Diskmaker X app. The app will offer to make installers for OS X 10.8, 10.9, and 10.10, but we're only interested in Yosemite today.Advertisement
Diskmaker X has actually been around since the days of OS X 10.7 (it was previously known as Lion Diskmaker), but it's more important now because Apple has made alterations to the installer that prevent easy USB drive creation using the built-in Disk Utility app. It's still possible to create a disk manually using a Terminal command (which we'll go into momentarily), but Diskmaker X presents an easy GUI-based way to do it that is less intimidating to most people.
Select OS X 10.10 in Diskmaker X, and the app should automatically find the copy you've downloaded to your Applications folder. If it doesn't detect the installer (or if you click 'Use another copy'), you can navigate to the specific installer you want to use. It will then ask you where you want to copy the files—click 'An 8GB USB thumb drive' if you have a single drive to use or 'Another kind of disk' to use a partition on a larger drive or some other kind of external drive. Choose your disk (or partition) from the list that appears, verify that you'd like to have the disk (or partition) erased, and then wait for the files to copy over. The process is outlined in screenshots below.
The only-slightly-less-easy way
If you don't want to use Diskmaker X, Apple has actually included a terminal command that can create an install disk for you. Assuming that you have the OS X Yosemite installer in your Applications folder and you have a Mac OS X Extended (Journaled)-formatted USB drive named 'Untitled' mounted on the system, you can create a Yosemite install drive by typing the following command into the Terminal.
Mac Yosemite Install
sudo /Applications/Install OS X Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install OS X Yosemite.app --nointeraction
Create Install Media Yosemite
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 OS X 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.
Install Yosemite From Usb
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 Yosemite as you normally would.