How to create an installation USB for Mac OS X Yosemite
This procedure works for Yosemite, but it should also work for the previous version of Mac OS X (Mavericks or Mountain Lion). But it will not work for Mac OS 10.6 (Snow Leopard).
Mac OS X Yosemite official page
The compatible Macs:
- iMac (Mid 2007 or newer)
- MacBook (late 2008 aluminum chassis, early 2009 or newer)
- MacBook Pro (mid late 2007 or newer)
- MacBook Air (late 2008 or newer)
- Mac mini (Early 2009 or newer)
- Mac Pro (Early 2008 or newer)
- Xserve (Early 2009)
- OS X 10.6.8 or higher
- 2GB of memory
- 8 GB of available space
- Some features require an Apple ID
- Some features require a compatible Internet package; subscription charges may apply.
- A least 4 GB of RAM.
- An existing iCloud account (Apple ID).
This will allow Mac OS X to automatically import the data already present on the Apple server during installation/upgrade. There procedure is optional and the step involving the creation of the iCloud account can be skipped during the installation of Yosemite.
You will also need a 8GB USB key.
STEP 1 - Download Yosemite
- Launch the App Store and sign in with your iCloud credentials.
- Click on OS X Yosemite.
- Click on the Download button (5.2 GB).
- The installation window automatically launches.
- Do not click on "Continue".
- Close the installation.
- Go to the Applications folder and locate the installation package: "Install OS X Yosemite"
- At this point you can the application to an external storage medium. The goal is to keep intact for possible future needs.
- Leave the original app in the Applications folder.
STEP 2 - Prepare the USB key
- Connect your USB key (not to the keyboard, but to the Mac itself) - run the Disk Utility located in Applications/Utilities ...
- In the left pane of the Disk Utility, select your USB key.
- On the right side of the window, click on the "Partition" button.
- In the "Partition Scheme" section, click on the "Current" button.
- Select "1 Partition".
- Click on the "Options" button.
- Select GUID and click on the "OK" button.
- Check that the chosen format is "Mac OS Extended (Journaled)"
- Name the key as yosem.
- At this point the key is ready.
STEP 3 - creating the installation USB
- Open the Terminal application located in Applications / Utilities ...
- Enter the below command:
sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/yosem --applicationpath /Applications/Install\ OS\ X\ Yosemite.app --nointeraction
- Confirm with "Enter" key
- Upon request, provide your administrator password
- Let the process unfold. It takes approximately half an hour.
- Your installation USB key is ready!
Update from a previous version
Mac OS X Snow Leopard
: If you are running Snow Leopard (10.6.x), make updates from the Apple menu > Software Update ...
- Your system will be updated to OS X 10.6.8, from there you can get Yosemite from the Mac App Store.
- Install Yosemite directly on your Mac.
- You will need to re-download Yosemite to get the installer.
- If you have Leopard (Mac OS 10.5) and want to upgrade to Yosemite, you must first install OS X Snow Leopard.