Make a bootable image copy of OSX 10.8 Mountain Lion after downloading the App from the store but before installing on your drive. Copy the image to a local drive or make a bootable external disk or DVD.
After downloading the Mountain Lion.App from the store aka “Install Mac OS X Mountain Lion”, find it in the /Applications directory, control click it to bring up a contextual menu and select “Show Package Contents” from the menu.
The older versions included in the list below are also stable but the Final Mac OS X Mountain Lion 10.8.X version is recommended fro users who want to get the most. Feb 17, 2012 Disk Utility will now create a bootable OS X Mountain Lion installer drive out of USB drive using the disk image, this can take a little while depending on how fast the drive and Mac are but 20-30 minutes isn’t unusual. Burn OS X Mountain Lion installer to single-layer DVD Authored by: lio256 on Oct 25, '12 01:02:43PM If you do want to get the Mountain Lion installer InstallESD.dmg to fit on a single layer DVD, you can use the overburn feature of hdiutil in Mac OS X. Create the Mountain Lion install drive Once you’ve purchased Mountain Lion, find the installer on your Mac. Right-click (or Control+click) the installer, and choose Show Package Contents from. In the folder that appears, open Contents, then open Shared Support; Launch Disk Utility. Aug 03, 2012 Question: Q: Install OS X Mountain Lion vs InstallESD.dmg I want to create a bootable copy of Mountain Lion, and I've been reading instructions on various forums, and they all say to copy the installESD.dmg file that's located within the Install OS X Mountain Lion.app.
show package contents
This brings up a Contents folder, from here navigate to Contents/Shared Support/InstallESD.dmg, and thats the disk image to burn, it contains all the goodies.
Double click it, you can skip the verifying process, then the disk image mounts as a volume in the sidebar.
Image to Bootable DVD
Select the mounted volume in the sidebar then either click on the burn icon if you have it set up or choose the option from the File menu, pop in a blank DVD and thats a job done. Mac os x lion dmg image download.
make-a-bootable-mountain-lion-image
You can also use /Utilities/Disk Utility to do the same thing, just launch Disk Utility, highlight the InstallESD.dmg and burn.
Copy to Local Drive
To keep a separate image of the dmg, option drag a copy to your desktop, this will make a copy of the InstallESD.dmg leaving the original Lion app intact.
Image to a Bootable External Disk
To make a bootable image to a drive instead of a disk, you need to do a restore in Disk Utility, select the InstallESD.dmg as the source and the disk volume as the destination. Enusure that the destination volume is correctly formatted as HFS+ Extended Journaled. Click “Restore”.
If you haven’t got the Mountain Lion App to start with and can’t re-download it from the App store, you can still make a partial boot drive from the hidden Recovery Partition, check it out.
Related
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.
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:
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.
Installesd.dmg Mountain Lion Windows 8
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.
Installesd.dmg Mountain Lion Windows 7
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).
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.