Running Mountain Lion on vSphere

The topic of this post has seen huge demands. So, I took the time to invest to run Mountain Lion (OS X 10.8) on vSphere! First of all, I found out no matter how hard I tried to get Mountain Lion to run on vSphere 5.0 U1, I failed:

  • Fresh install on vSphere 5.0 U1
  • Update existing Virtual Machine running Lion
  • Importing a Virtual Machine running Mountain Lion from VMware Fusion

Therefore I assumed I had no other chance than to wait until the release of VMware vSphere 5.1…

Alright, here’s the instruction to run Mountain Lion on vSphere. You need to follow the steps outlined below to successfully install OS X 10.8 on vSphere 5.1. For an existing Lion VM you need to follow the steps 1 thru 5. For a fresh installation, you can skip step 5.

  1. Install vSphere 5.0 Update 1 on your Mac Mini.
  2. Update existing VMware vSphere 5.0 Update 1 installation
  3. Purchase & download Mountain Lion from Mac App Store
  4. Convert installation package to an ISO file.
  5. Upgrade an existing Lion VM
  6. Create a new Virtual Machine
  7. Start up the Virtual Machine and install Mountain Lion


Step 1 “Installing vSphere 5.0 Update 1 on your Mac Mini”

Instructions can be found here

Step 2 “Update existing VMware vSphere 5.0 Update 1 installation”

To successfully complete this step you need to have a valid VMware account and either use a 60-day evaluation version or a valid license key (you need to a new license key for ESXi 5.1). You can download VMware vSphere 5.1 here. As soon as you have downloaded your image you need to either burn it to a CD-ROM or copy it to a USB stick with the method described in step 2.

Insert your USB stick or attach your CD-ROM Drive with the vSphere 5.1 image to your Mac Mini. Update your existing vSphere 5.0 U1 installation by starting up your Mac Mini and holding down the Alt/Option key on your keyboard. After the POST you will be presented with a boot options menu, choose your device with the vSphere 5.1 image on it. When presented with the options menu from the VMware vSphere 5.1 installer, choose option 1: Upgrade ESXi, preserve VMFS Datastore. This upgrade will not only preserve your VMFS Datastore but also, equally important, your existing, customised Broadcom Ethernet adapter driver. If you are running an existing VMware vCenter be sure to upgrade it before you upgrade your servers. For instructions on how to do that, please consult the following VMware white paper for upgrading your environment and its preparation checklist.

After a successful upgrade the specifications of your Mac Mini Server should look similar to this picture:

MacMini vSphereafterupgrade

Step 3 “Purchase & download Mountain Lion from the Mac App Store”

Macappstore osx

Step 4 “Convert installation package to an ISO file”

Install mtnlion

Instructions can be found here.

You can skip step 5 if you don’t have an existing Lion VM or if you want to create a new VM, anyway.

Step 5 “Upgrade an existing Lion VM”

First off all, take a snap shot of your existing Lion VM. It’s always important to have a fail back option.


Start up your Lion VM and connect the Mountain Lion ISO-file.


Launch the Console and in the Console start the installation of Mountain Lion

Vm upgrade mtnlion

Follow the instructions shown on screen. After roughly 30 minutes you are presented with an upgraded version of OS X.

Vm success

Step 6 “Create a new Virtual Machine”

Connect to your ESXi-Server or VMware vCenter server. Create a new Virtual Machine with VM Hardware version 9.

Createvm v9

Choose Mac OS X Lion 10.7 (64-bit) as the guest OS of your choice.

Createvm guestos

Go to New CD/DVD Drive and choose the option to select a Datastore ISO File. Browse to the ISO-file you created in the previous step. Check Connect at Start-up .

Createvm iso

Check the specifications of your Virtual Machine. If the settings are correct, click on finish.

Createvm rtc

Step 7 “Start up the Virtual Machine and install Mountain Lion”

Power on your newly created Virtual Machine and launch the console to watch it boot. After a couple of minutes you are presented with the installation screen for Mountain Lion.

MtnLion vSphere5

If not, check the following:

  1. Does the CD-ROM connect at start-up?
  2. Are your VM settings correct?
  3. Is the vSphere server running vSphere 5.1?
  4. Is your ISO-file working (mount it to an existing Mac OS X installation)?

After roughly 30 minutes of installation time you will be presented with Mountain Lion!


Have fun!

12 thoughts on “Running Mountain Lion on vSphere

  1. Doug

    Now with ESXi 5.1 I can finally boot the Mountain Lion install iso. But for me the installer fails with “Can’t download the additional components needed to install Mac OS X”. I do have network connectivity because I can browse the Apple support page from within the installer. I guess I’ll try installing it in Fusion first and then moving it over.

    1. That’s strange, as you wrote you may want to try the Fusion install, first. You can pull it over, but you may need to convert the vmdk with vmkfstools. I could install it directly on my Mac Mini running vSphere.

      1. Doug

        You know what, as I was installing it in Fusion I tried it in ESXi one more time and it went through. So who knows why it wasn’t working the first couple of times. Thanks again for posting that link to ESXi 5.1, I finally have it working!

  2. ursula brunner

    Gratulation to you! You are a very strong working men all over the world and in the clouds…. You are fliing through the clouds, you are working in the clouds, your life is in the clouds and your remember will be in the clouds….. Yes or no??? Yes, really, my dear Marcel! Kind regards UB

    1. Hi Luca, are you running the latest version of vCenter (5.1) and its vSphere client (I recommend the Web client)? It should say either compatible with vSphere 5.1 and later and in bracket it says Hardware version 9.

      1. Luca

        no i’m running only the hypervisor and the vSphere Client, the HW version 9 option is “hidden” in the VM menu “upgrade hardware”, i’m trying now to install vCenter 😉

  3. Joe

    Is having a vCenter managed ESXi box required to have the option for hardware version 9? I too am running the free ESXi, and version 8 is as high as it goes…

  4. Michael

    Everything goes beautifuly until the rebbot after the install. It just hangs at the Apple Logo and the gear just spins. I thought it was gonna work for a minute there as I said it went so smooth. I have ESXi 5.1 with Vsphere 5.1. Any other ideas? I have spent 3 days and up late til 4:00 in the morning. LOL! Getting frustrated but would really love to get this going now. Im on a mission. Any suggestions would be greatley appreciated.

    Thanks in advace..

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