Easy Mac Hacks: How to Install OS X from a Bootable USB Drive

Every Monday we show you how to do something quick and cool with Mac OS X. Sometimes it's a tutorial on a lesser-known feature, other times it's a trick that uses built-in functionality such as Terminal — either way, these simple tips can make life better and easier, and they don’t require any special knowledge. All you need to do is follow the instructions!

Maybe you've just replaced a drive in your Mac and need to reinstall Yosemite, or perhaps you need to upgrade a Mac to the latest operating system without taking it online. Whatever your reason, there is a simple way to make a bootable drive of the OS X Installer so that you can easily update your operating system.

What You'll Need:

• USB thumb drive or hard drive with at least 8GBs of space available
• OS X Yosemite Installer from the Mac App Store
• DiskMaker X (This is an AppleScript app that will automatically format the drive you want to use as a bootable disk, then copy over the installer so that the disk can be used to boot into the OS X Installer.)

Once you have these items available, you'll be ready to begin creating the bootable installer by following these steps:

1. Connect the drive that you want to use as a bootable disk to your Mac.
2. Open the DiskMaker X app, then select either "An 8GB USB thumbdrive" or "Another kind of Disk" when the app launches.
3. When prompted, select the name of the drive that will be used as a bootable drive.

After doing this, DiskMaker X will spring into action and format the drive, then proceed to copy over the installer files. By default, it should automatically find the OS X Installer inside of your Applications folder. If it doesn't, then you'll be prompted to select its location.

This process can take a while depending on the speed of your Mac — anywhere from 30 minutes to an hour. When the process has been completed, you'll see a confirmation dialog appear, and you'll be able to safely eject the drive.

To use the installer to load Yosemite onto a computer, boot or reboot the Mac while holding down the Option key, then select the drive from the choices displayed. You'll be booted into the OS X Yosemite installer.