With Mountain Lion's InstallESD.dmg file copied to the Desktop (see previous page), we're ready to burn a bootable DVD of the installer. If you would rather create a bootable copy on a USB flash drive, you can skip this page and go on to the next page.
- Insert a blank DVD into your Mac's optical drive.
- If a notice asks you what to do with the blank DVD, click the Ignore button. If your Mac is set up to automatically launch a DVD-related application when you insert a DVD, quit that application.
- Launch Disk Utility, located at /Applications/Utilities.
- Click the Burn icon, located in the top right corner of the Disk Utility window.
- Select the InstallESD.dmg file you copied to the Desktop in an earlier step.
- Click the Burn button.
- Place a blank DVD into your Mac's optical drive and click the Burn button again.
- A bootable DVD containing OS X Mountain Lion will be created.
- When the burn process is complete, eject the DVD, add a label, and store the DVD in a safe location.