2 Replies Latest reply: Jul 20, 2012 3:17 PM by Neville Hillyer
mrbillbailey Level 1 (0 points)

I'm trying to upgrade my OS from my current 10.5.8 to the most recent version of the OS.  Do i have to do implemental upgrades, or can I go directly to Mountain Lion with one installation.


Any help would be appreciated.





macbook, Mac OS X (10.5.5)
  • Kappy Level 10 (265,951 points)

    Not possible until you have at least upgraded to Snow Leopard 10.6.8 because you need it to access the App Store where you will purchase and download Mountain Lion when it is released.


    Upgrading to Mountain Lion


    You can upgrade to Mountain Lion from Lion or directly from Snow Leopard. Mountain Lion can be downloaded from the Mac App Store for $19.00. To access the App Store you must have Snow Leopard 10.6.6 or later installed.


    Be sure your computer meets the minimum requirements:


    Apple - OS X Mountain Lion - Read the technical specifications.


    Macs that are NOT expected to support OS X Mountain Lion


    Older Macs and those with weaker GPU’s will likely be left behind:

    1. Anything with an Intel GMA 950 or x3100 integrated graphics card
    2. Anything with an ATI Radeon X1600
    3. MacBook models released prior to 2008
    4. Mac Mini released prior to 2007
    5. iMac models released prior to 2007
    6. Original MacBook Air


    Your model must have a 64-bit EFI boot ROM. See OS X v10.6- Macs that use the 64-bit kernel


    An easy way to tell if you are running a 64-bit kernel is to use the uname command-line program. Open the Terminal in the Utilities folder and enter the command line:


              $ uname -a


    Press RETURN.


    The "x86_64" in the excerpt below means that you are running a 64-bit kernel. If the output showed "i386" instead, that would mean a 32-bit kernel.


              $ Darwin... root:xnu-1456.1.25~1/RELEASE_X86_64 x86_64


    If your computer does not boot into the 64-bit kernel automatically you can force it to by restarting and holding down the "6" and "4" keys after the chime. Re-run the above command in Terminal. If you don't see "x86_64" then your model does not have a 64-bit EFI boot ROM and cannot boot Mountain Lion.


    Are my applications compatible?


    See App Compatibility Table - RoaringApps - App compatibility and feature support for OS X & iOS.


    Am I eligible for the free upgrade?


    See Apple - Free OS X Mountain Lion upgrade Program.

  • Neville Hillyer Level 4 (1,865 points)

    Before the install

    Ensure your data (at least all Home folders) is backed up before you install. Hard disks can fail at any time so it is important to regularly backup to an external disk with Time Machine or a third party alternative. Inexperienced users should follow Apple's install advice but experienced users may prefer to do a clean install.


    OS numbers and names

    OS X 10.4.x - Tiger

    OS X 10.5.x - Leopard

    OS X 10.6.x - Snow Leopard

    OS X 10.7.x - Lion

    OS X 10.8.x - Mountain Lion


    More about Macs

    The Apple History site has specifications for every Mac ever produced: http://www.apple-history.com


    Upgrade to Leopard

    Those wishing to upgrade to Leopard should be aware that install disks can be expensive. Details: http://lowendmac.com/deals/best-os-x-leopard-prices.html Standard Leopard installers impose several hardware limitations including speed and RAM size but all these restrictions can be overcome. Google for details. Leopard works well at 500 MHz with 1 GB of RAM and many happy users have less than this.


    Upgrade beyond Leopard

    OSs beyond OS X 10.5.8 require an Intel processor. If in doubt click the apple at the top left of your screen and select 'About this Mac'. This will give you your OS number. Then click 'More Info' to see which processor you have. If it says PowerPC you cannot upgrade to Snow Leopard and above. If you have an Intel Mac it is well worth upgrading to Snow Leopard now and then considering other options after that. You can buy Snow Leopard here: http://store.apple.com/us/product/MC573Z/A


    Upgrade beyond Snow Leopard

    Information about upgrading Snow Leopard to Lion or Mountain Lion: http://store.apple.com/us/product/MD256Z/A



    1. Check that your Mac complies with any requirements.
    2. If you are not in the US you should use the Change Country link at the bottom of Apple pages.