Jul 25, 2012 Apple has released its OS X 10.8 Mountain Lion (see CNET's full review) and it's available for download from the Mac App Store on systems running OS X 10.6.6 or later.If you're interested in the. Mac OS X Mountain Lion (version 10.8) is the nineth major release of Mac OS X (now named macOS), Apple's desktop and server operating system for Macintosh computers. OS X Mountain Lion brings a lot of great things from iPhone, iPad, and iPod touch to the Mac. You can send iMessages. Get your Mac in on Game Center. This post explains how to prepare a bootable mountain lion OS X 10.8 image (and ISO) for VMware from original dmg file. It can be used on Windows 7 with normal Intel based computer.

Mac OS X Mountain Lion (version 10.8) is the nineth major release of Mac OS X (now named macOS), Apple's desktop and server operating system for Macintosh computers.

OS X Mountain Lion brings a lot of great things from iPhone, iPad, and iPod touch to the Mac. You can send iMessages. Get your Mac in on Game Center. Receive notifications. And more. And with iCloud, now your Mac works even better with your iOS devices.

General requirements

Mac computer with an Intel Core 2 Duo, Core i3, Core i5, Core i7, or Xeon processor
2 GB or more of memory
8 GB or more of available space

Supported Macs

iMac (Mid 2007 or newer)
MacBook (Late 2008 Aluminum, or Early 2009 or newer)
MacBook Pro (Mid/Late 2007 or newer)
MacBook Air (Late 2008 or newer)
Mac mini (Early 2009 or newer)
Mac Pro (Early 2008 or newer)
Xserve (Early 2009)

I own a Macbook Air and wanted to extract an OS X 10.8 Mountain Lion InstallESD.dmg from the Air. However as OS X 0.8 Mountain Lion came installed on my Macbook Air i could not obtain the InstallESD.dmg from the App Store.

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So i needed some way to obtain the InstallESD.dmg, this would allow me to burn it to disc (if my Air had a DVD drive) create an installable USB stick for OSX or simply create an ISO so i can burn the install DVD on Windows.

It turns out you can extract a full OS X 10.8 Mountain Lion install disc from your Macbook Air / Pro quite easily. I found some old instructions on Macworld aimed at doing the same for OSX Lion on a Macbook Pro also worked for OSX Mountain Lion on my Macbook Air.

Here is how i obtained my InstallESD.dmg From my Macbook Air:

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1. Open the Terminal, and type this command to list all partitions on your hard drive or SSD:

diskutil list

2. Look for ‘Recovery HD’ in the list, and note its identifier. It will be something of the form diskXsY, where X and Y are numeric digits, for me the identifier was disk0s3

3. Type the following command to mount the recovery HD:

diskutil mount readOnly /dev/[identifier]

4. Replace [identifier] above with the identifier you obtained from step 2. So on my machine, I typed:

diskutil mount readOnly /dev/disk0s3

Your identifier could be different

5. The disk image inside the recovery HD is invisible, so use the Terminal to mount that too:

hdiutil attach “/Volumes/Recovery HD/com.apple.recovery.boot/BaseSystem.dmg”

6. Now, from the newly mounted Mac OS X Base System image, double-click the ‘Install Mac OS X Mountain Lion’ application at the root of the disk.

7. Go through the license agreement. Once it asks you for a disk to install on, choose the external drive or spare partition. For this i used a 16gb USB memory stick.

8. Enter your admin password when prompted, and the installer will start downloading.

When the download has finished the installer will re boot your Mac, so we need to stop it from doing this.

MacWorld had the following tip:

Open an old-style (non-autosaving) application that still uses the traditional Save, Save As…, etc. commands in the File menu (I used TextWrangler) and make a new unsaved document, and type a few things in it. This will give you a little insurance against the installer rebooting the system, since the app won’t let the system reboot until you respond to its message asking whether you want to save the document or not.

I just kept an eye on it and force closed it before the timer counted to 0.

9. Once the file finishes downloading, the installer will extract the InstallESD.dmg image from it and delete the package. This will be fine as long as you don’t let the app restart your machine. Once the installer finishes download and prompts you to restart your Mac, force-quit it. Do this quickly, as it may automatically reboot for you after a 30 timeout period (although if you’ve got an unsaved document open, you should be able to prevent that).

Mac Os X Mountain Lion 10.8 Download Free

10. If we look at the USB drive we told OSX to save the data to you should see an OS X Install Data folder

11. Open the OS X Install Data folder and you will find an InstallESD.dmg

12. This is your full OS X 10.8 Mountain Lion install disc, you can burn it to a DVD, image it to a USB flash drive to create a USB installation disc or use dmg2iso to convert the DMG to an ISO which can be burned by a popular image burning application, such as ImgBurn on Windows. The ISO can be used on Esxi, VmWare and so on if you decide to convert the DMG to an ISO.

13. The end result is your choice of installation media for OS X 10.8 Mountain Lion, I wanted to obtain an ISO so i could install OS X 10.8 Mountain Lion on my VmWare Esxi Server. As you can see OSX 10.8.3 was downloaded, as 10.8.4 was only released a few days ago i imagine eventually you should be able to get an up to date install dmg by doing this.

Mac Os X Mountain Lion 10.8 Dmg