There are other methods for creating a bootable Mountain Lion disk. if DiskMaker X is giving you problems let's just move on to the next method.
Method 1: createinsallmedia
(You can use this method within 10.10 (Yosemite) but you will not be able to use this method once you are running 10.8 (Mountain Lion) as this software was not introduced until 10.9 (Mavericks). At which point you will need to use Method 2 detailed below)
- Rename your desired flash drive "MLInstaller"
- Launch the Terminal application, found in /Applications/Utilities/ and enter the following command
Code:
sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/MLInstaller --applicationpath /Applications/Install\ OS\ X\ Mountain\ Lion.app --nointeraction
- You’ll then see the following screen text in the Terminal:
Code:
Erasing Disk: 0%… 10%… 20%… 30%…100%…
Copying installer files to disk…
Copy complete.
Making disk bootable…
Copying boot files…
Copy complete.
Done.
That's it you're done.
Method 2: Disk Utility
- Secondary click on the installer and click 'Show Package Contents'.
- Open 'Contents' folder, open 'SharedSupport' folder next.
- You will now see a disk image called 'InstallESD.dmg'. (Move this finder window to the side)
- Open the Disk Utility App which will be found in /Application/Utilities
- Insert you flash drive and make sure it's formatted to 'Mac OS Extended (Journaled)'
- Now you are going to drag 'InstallESD.dmg' into the white pane on the left side of Disk Utility
- Select your Flash Drive, than click 'Restore' on the main window.
- Drag the 'InstallESD.dmg' into the source field and select your flash drive as the destination drive.
If you get the "Could not restore – Invalid argument" error at the end of the restore process, you can safely ignore it and move on.