How to Burn a Mountain Lion Install Disk on DVD or USB

Users can now download and install OS X 10.8 Mountain Lion from the Mac App Store. Apple wants users to download it on each system from their store, but that can take up precious time and bandwidth. Why not download it once and then install from that download to each system.

For example, I use a MacBook Pro, MacBook Air and a Mac Mini. Why must I download the upgrade three times on each system?

Users don’t have to download the upgrade on each system if they follow the steps below for creating a DVD or USB install disk with Mountain Lion’s upgrade installation on it. The user can also work with an SD card but that’s not recommended since some machines might not boot to an SD card.

The easiest option includes installing a really simple utility. I recommend this easy option, but if a user doesn’t want to bother with third-party software, even if it is free and safe, then we offer a second alternative that takes a little more work.

Mountain lion update

Before performing either method of upgrading, be sure to follow our guide for getting ready for Mountain Lion.

Use Lion Diskmaker App

The option involves downloading and installing the free app Lion Diskmaker. The app looks for the downloaded installation files in the Application folder. Download the Mountain Lion installation files from the Mac App Sore then run the free app. It finds the files and then burns them to a flash drive or DVD.

I recommend using the USB option since it runs the installation faster than a DVD and future Macs likely won’t ship with a DVD drive.

Do the following:

  1. Download the Mac App Store Mountain Lion install files but don’t actually update your version of OS X at this point.
  2. Run the Lion Diskmaker and follow the app’s instructions using an 8GB USB drive or double layer DVD. Note single layer discs won’t work and the app will erase the USB drive.
  3. Test the DVD or USB disk to see if the app burned the files correctly by doing the Mountain Lion update from the disk (boot the computer while the holding down the Option key).

This should update any system with Mountain Lion.

DIY Method for Those Wanting to Avoid 3rd Party Software

Note that I’ve not tested this procedure since the first one works so much better, but it should work fine. Thanks to Lifehacker for the steps.

  1. Download the Mac App Store Mountain Lion install files but don’t actually update your version of OS X at this point.
  2. Open the Application folder and find the installer app and right-click it to and choose Show package contents.
  3. Find the InstallESD.dmg file inside the Contents > SharedSupport folder.
  4. Open the Disk Utility app in the Utilities folder under Applications.
  5. Drag the installESD.dmg image file into the sidebar on the left of the Disk Utility app.
  6. Insert either a blank double-layer DVD or an 8GB USB drive.
  7. DVD Users only: Select Burn after selecting the DMG image file and then boot from the disk by restarting the Mac and then holding down the Option key as it books up. Choose the disk as the startup option and install Mountain Lion. Quit here.
  8. USB Users only (from here to end): Select the USB disk in the Disk Utility and choose the Partition tab and select 1 Partition from the drop down box and Mac OS Extended (Journaled) in Format type.
  9. Click Options and choose GUID Partition Table.
  10. Hit Apply to erase and partition the drive so it will boot properly.
  11. Click Restore and choose the DMG file as the source and the USB drive as the destination and hit Apply.
  12. Boot the Mac with the USB drive by holding down the Option key as the computer starts and then run the update.

These steps work but they’re much more complicated. The above Lion Diskmaker app makes this much simpler.

For users with a cluttered system that suffers from instability, this might offer a great time to erase the system and install a fresh installation of OS X. Back everything up and make sure all the software installation files and their activation serial numbers or keys are accessible.

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