Navigate to where you saved the “InstallESD.dmg” file and select that. When you click on the “Burn” icon, you will be asked which image you would like to burn. (Note: untested instructions for how to make a bootable USB thumb drive are below as well.)įirst, launch the “Disk Utility” application. I only had a single-sided DVD so I’m showing the steps here that you would use. As I already said a few times, you need a dual-sided DVD (see step 4a below on how to burn a single-sided DVD).

Step Four – Burn the DVD (or the USB drive) Remember the location where you put that. You will need this file (“InstallESD.dmg”) for the bootable DVD. To do this, right-click on the Installer file and choose “Show Package Contents”.įrom within the Package Contents, navigate to: Contents > Shared Support and select the “InstallESD.dmg” file and COPY that back to your Desktop (or wherever you want). Step Three – Show Package Contents & Copy the Installer Fileįrom the copy that you created of the installer (e.g., the one on your Desktop), you will need to extract the actual installer DMG from the Package Contents. You can see that the installer is about 4.37 GB (as I mentioned before, the expanded size is LARGER than what will fit on a single-sided DVD so get a dual-sided DVD). Then, go into your “Applications” folder and copy the Mountain Lion Installer to another location like your Desktop. You need to STOP that lion in it’s tracks right there. The installer will automatically launch once it is completed downloading. Step Two – Quit the Installer Once it’s Finished Downloading & Copy Then sit back and wait while it downloads. If you have already purchased Mountain Lion, check your “Purchases” section and you can download from there. Head over to the Apple App Store and download the installer. Step One – Download the Mountain Lion installer

UPDATE 07.26.12 – Thanks to commenter Benoit’s comments, you can now burn a single-sided/single-layer DVD. You MUST have a dual-sided DVD in order to burn the DVD. NOTE: The expanded size of the Mountain Lion installer will NOT fit on a single-sided DVD. So, if you do want to create an installer DVD (and you could do this with a USB drive as well), here are the steps to do so. But what if you want to install Mountain Lion on another computer (that is supported)? There is a way to easily do this, but remember, you should only do this with computers that you own or manage (and you wouldn’t need to do this if you had all of your computers use your Apple ID in the App Store – you would just install right from there). Just head over to the Apple App Store on your supported Mac and purchase and install Mountain Lion now! As part of the upgrade process, your Emergency Recovery Boot Partition will be upgraded to support re-installs of Mountain Lion without the need for an external installer. “ Mountain Lion,” is officially available for purchase and download. As many people know, Apple’s new Operating System, OS 10.8 – a.k.a.

Create mac os lion bootable usb