Once it is running you will see a list of the mounted drives connected to your Mac. Launch the Disk Utility application located in your Application’s Utilities folder. Take a thumb drive that has at least a 8GB capacity, and connect it to your Mac. This file is a bootable disk image of OS X with the Mountain Lion Installer already installed. The following is a quick guide to help you create a USB installer for Mountain Lion, very similar in fact to the OS X Lion USB Thumb Drive Apple use to sell with previous versions of OS X.Īfter purchasing and downloading the OS X Mountain Lion update and before actually updating your Mac, navigate to your Applications folder in the Finder and right click on the file “Install Mac OS X Mountain Lion.app” and select “Show Package Contents.” Look in the “Shared Support” folder located under the “Contents” folder of the “Install Mac OS X Mountain Lion.app,” and copy the file named “InstallESD.dmg” to your desktop. But there are times when it’s more useful to have a means to install OS X from an external source. Perhaps you have a fast broadband connection at home or work and downloading multiple copies of OS X Mountain Lion(s AAPL) from the Mac App Store to update a few computers is not an issue.
