OS X Lion had planned for two distribution channels from the Mac App Store and on CD, but after an experiment, Apple decided that OS X Mountain Lion would be distributed exclusively by theMac App Store to cut costs and make more convenient distribution (which is very bad for countries like India where download speeds are very low). This eliminates the possibility of having a physical support that we can pull through, but in this post I will explain how to install OS X Mountain Lion on a flash drive, that may be used to install it on other Macs or for recovery later on.
The first thing to do, evidently, is to download OS X Mountain Lion from the Mac App Store and then follow a few simple steps :
Once downloaded, we need to go to the Applications folder and find the installer for OS X Mountain Lion , to click the right mouse button which will Show Package Contents, and find the file by following the path / Contents / Support Shared InstallESD.dmg . Now we have to restore this disk image on our flash drive with Disk Utility.
We have to open Disk Utility, make sure the flash memory or external hard drive is formatted “Mac OS Extended (Journaled) ”and check the options in the partition as the partition type is”GUID Partition Table . ”
Once secured the points in the Restore tab, we have to drag the file InstallESD.dmg in the Source box, and click the Restore button. Now we have to drag the newly formatted disk in the Target text box and press the reset button. The process should take about 30 minutes.
In addition to this procedure, we can use the application Lion Diskmaker , which automates and simplifies the process . Once downloaded the application, we have to select which version you want to install in flash memory, select Create a boot disk and select the flash memory that we want to use.
This flash will give us the same options as the emergency recovery partition : Use Safari to find information on troubleshooting, run Disk Utility to correct the errors in the file system, restore from a Time Machine backup or install Mountain Lion from scratch on any Mac compatible. And as always, before venturing to do anything new, it is advisable to back up your system.