Updated
February 29, 2016.
Installing OS X Yosemite hasn't changed a great deal since OS X Lion changed the delivery of the OS from optical disks to electronic downloads, using the Mac App Store.
The big advantage to downloading OS X is of course immediate gratification (and not having to pay shipping charges). But the downside is that the installer you download is deleted as soon as you make use of it by installing OS X Yosemite, or for that matter, any downloadable version of OS X.
With the installer gone, you lose the opportunity to install the OS on more than one Mac without having to go through the download process again. You also lose out on having an installer that you can use to perform clean installs that completely overwrite your startup drive, or having an emergency bootable installer that includes a few useful utilities that can bail you out of an emergency.
To overcome these limitations of the OS X installer, all you need is a USB drive that contains a bootable copy of the installer.
How to Create a Bootable OS X Yosemite Installer on a USB Drive
There are two ways to make a bootable copy of the installer; one makes use of Terminal, the command-line utility included with all copies of OS X; the other uses a combination of the Finder, Disk Utility, and Terminal to get the job done.
In the past, I've always shown you the manual method, which uses the Finder, Disk Utility, and Terminal. Although this method involves more steps, it's easier for many Mac users because the majority of the process uses familiar tools.
This time around, I'm going to show you the Terminal app method, which uses a single command that's included in the OS X Yosemite installer you downloaded. Don't worry; if you would rather use the method we've used in the past, I'll be providing a guide for that method as well.
Use Disk Utility to Create a Bootable OS X Yosemite Installer
Start By Not Starting
Before you begin, stop. That may sound a bit daft, but as I mentioned above, if you use the OS X Yosemite installer, it will delete itself from your Mac as part of the installation process. So, if you haven't yet used the installer you downloaded, don't. If you've already installed OS X Yosemite, you can re-download the installer following these instructions:
If you're just now downloading the installer, you'll notice that once the download is complete, the installer will start up on its own. You can just quit the installer, the same way you'd quit any other Mac app.
What You Need
- You should already have the OS X Yosemite installer on your Mac. It will be located in the /Applications folder, with the name Install OS X Yosemite.
- A USB flash drive. You can use any USB drive that is 8 GB in size or larger. The actual size of the bootable version of the installer comes in at a tad over 5 GB.
- A Mac that meets the minimum requirements for OS X Yosemite.
If you have everything you need, let's get started.
Published 8/19/2014
Updated: 2/29/2016
