How To Install Mac OS X From A USB Memory Stick

Written by John Thompson on November 26, 2010 · Filed under How To, Software 

I recently had a bit of a Mac-related disaster when I decided to upgrade one of my Mac OS X computers to Snow Leopard, only to find that the optical drive decided to be stubborn and spit out discs right left and centre. Not one to be defeated, I tried a different approach: USB installation.

MacBook Air owners will know how painful it can be to use remote disc install for various installations, so to be able to install not only applications, but also operating system updates, via USB is a big advantage.

The MacBook Air isn’t the only Mac now without an optical drive either; the Mac Mini server edition sacrifices the optical drive for an additional hard drive.

If you want to know how I got on, and how you can install Mac OS X via USB, then carry on reading to check out the guide!

What You’ll Need

To be able to install Mac OS X via USB, you’re going to need your Mac OS X installation disc (if you haven’t got one, Snow Leopard costs just £25 from Apple), a pen drive with a capacity of at least 8GB (the Snow Leopard DVD comes in at just over 6GB), and a Mac with an optical drive that you can use to transfer the files over. If you haven’t got one, try to borrow one from a friend; any Mac will do this.

Preparing and Putting OS X on the USB Drive

Once your pen drive is in your computer, you need to open Disk Utility, which is a tool that comes with every Mac. Select your USB memory stick from the menu on the left, and then go to the “Erase” tab. You’ll want to format the drive as a “Mac OS Extended (Journaled)”, and it might be a good idea to give it a memorable name such as “Snow Leopard Install” so that you don’t lose track of it when you need it later!

With the drive restored, you can now put the necessary data on to it from the Snow Leopard installation DVD. Doing this is simple with the help of Disk Utility. With your Mac OS X DVD inserted in to your computer, select the “Restore” tab in disk utility.

You’ll notice “Mac OS X Install DVD” present on the disk utility menu. You’ll need to drag this in to the “Source” field of the restore tab. For the destination, you should drag the partition you just created in to the field. Click the restore button, and all the files from the DVD will begin to copy over. The process took around half an hour on my machine, but speeds may vary depending on your setup.

Installing Mac OS X

When the restore has been completed, with a bit of luck things should be plain sailing from here. Make sure your USB drive is in the computer that you want to install Mac OS X on to, and then boot up holding the option (Alt) key. You will have at least two sources from which to boot, one of which will be the USB drive you just created. Select this option, and begin the OS X installation process like you would with the OS X DVD.

The advantage to using a USB drive for installation is that it should be considerably quicker than it would be via DVD. I was pretty amazed to see Mac OS X installed and ready to use in just 12 minutes, which is miles quicker than it usually takes via DVD.

Once OS X is installed, your Mac will reboot, and proceed to boot in to OS X. Mission accomplished!

If you have any questions about how to install Mac OS X from a USB memory stick/flash drive, don’t hesitate to leave them in the comments, and either myself or a commenter in the know will gladly get back to you!