Install OS X 10.8 Mountain Lion in VMware Fusion 4.1.3 (clean installation, not upgrade)

Previously I’ve been using older OS X virtual images and upgrading them as needed.  Looking back through some notes about various utilities, features, and command line tools, I noticed something which I wanted to test on a clean installation.

Sometimes new versions of OS X remove some features, but upgrading over an old installation (instead of doing a clean install) may leave the old feature or utility in place and available.  In order to verify whether Mountain Lion removed some utilities previously available in Snow Leapoard and Lion, it seemed like a good time to test the process of creating a clean VM installation from the App Store downloaded installation file for OS X 10.8 Mountain Lion.

Within VMware Fusion 4.1.3 (the latest release version at this time):

  • make sure you have an available copy of the App Store download for Mountain Lion
  • create a new VM
  • select “Continue without disc
  • on the next screen “Choose a disc or disk image…” and navigate to “Install OS X Mountain” file.  (When initially downloading this file, the App Store places it in your Applications Folder.  On most systems it gets automatically removed after the upgrade/installation is completed.  So prior to running it, it is a good idea to back up a copy to another location.  The copy can be used to upgrade other machines, or for creating VMs as we’re about to do now.)
  • select “Continue” on the next few screens to accept the defaults and start the VM.  The defaults should be adequate for most initial testing and I’d recommended them until you get more familiar or identify a specific need to customize settings further.
    • note: if you have a folder of application install files, it is helpful to configure Fusion’s “file sharing” options to present that folder within the VM when it is running.
  • At the end of the settings screens, select the “Finish” button.  Fusion will complete the configuration and start the VM.

The VM may seem to start very slowly before presenting the initial grey OS X booting screen.  And will likely take some time, perhaps several minutes unless you’re on an Ivy Bridge / SSD system (if you are on a 2012 Ivy Bridge CPU and encounter a CPU error from Fusion, this post explain how to modify your VM config to continue).

Eventually you should see the “OS X Utilities” window and have the option to select “Reinstall OS X“.  Select “Continue” a couple times, then “Agree” to the license (twice), select the hard drive “Macintosh HD” and “Install“.

The installation proceeds without an further interaction until it automatically reboots.  After the VM reboots, the “Install OS X” screen will appear and display a progress indicator.  On an older CoreDuo MacMini, it took about ten minutes to reach the reboot and then displays an estimate of about 20 minutes to complete the installation.  ActivityMonitor shows this old MacMini is CPU constrained, but I’m waiting for next refresh to include Ivy Bridge and USB 3 before getting a new one.

When the installation process completes, the VM will reboot and present the “Welcome” screen to begin the initial configuration of OS X.  If audio is enabled, you should hear a voice welcoming you to setup.

  • select a Country
  • select a Keyboard Layout
  • choose whether to Transfer Information using Migration Assistant.  If you haven’t used it before, it can move information from other Macs, Windows PCs, or TimeMachine backups and works pretty well for a wide variety of application settings and user data.   Since the goal is testing a clean installation of OS X 10.8 Mountain Lion, I won’t be using Migration Assistant this time.  It can also be ran later, so it’s not critical to decided right now.
  • choose whether to enable “Location Services” (I’m leaving it disabled on this VM).
  • Enter you AppleID to setup App Store, iCloud, etc.  I have separate IDs for iTunes and iCloud, and don’t need either configured on this VM right now.  So I’m selecting “Skip” on this setup screen.
  • accept the “Terms and Conditions” (twice again).
  • fill in the fields for “Create Your Computer Account” to establish your username and password.
  • Select Your Time Zone” by clicking the map and selecting a nearby city.
  • Register“.  I’ll “Skip” this screen for this VM.
  • and finally you reach the “Thank You” screen and can “Start using your Mac“.

At this point you get the new OS X Mountain Lion (fortunately it does not inflict another reboot on you here) and you are ready to go.

Since my goal was to configure a cleanly installed VM for some testing, I’m going to stop here, shut down the VM, and make a Zip Archive of the VM’s file image for later re-use.  Once that housekeeping task is complete, then I’ll review my notes on previous versions and retest various utilities to see what still works.  Results will be documented in a follow up post.


Summary:  Using the “Install OS X Mountain” file to create a new virtual machine in VMware Fusion 4.1.3 is quick and easy.

2 thoughts on “Install OS X 10.8 Mountain Lion in VMware Fusion 4.1.3 (clean installation, not upgrade)

  1. Most appreciated. Thank you. I have resisted moving on from Syst 16.8 (10.6.8), but some aspects of Syst 18 (10.8) are attractive, so this will allow a wonderfully safe and secure means of checked things out without having to compromise a stable setup. (I’ll probably do what I’ve done for the last 10 or so OSs – use the previous one until the latest one is in turn replaced, then use *that new previous version


  2. to disable hibernate (aka safe sleep) in Mac OS X, use these terminal commands:
    * disable safe sleep mode: sudo pmset hibernatemode 0
    * remove the sleep image file: sudo rm -rf /var/vm/sleepimage


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