How to install Mac OS X Leopard on unsupported Macs

“Apple usually weeds out a few machines with new versions of OS X, but 10.5 is the first release I’m aware of that will exclude a larger number of machines from being able to run the new OS. For example, my trusty G4 fails to meet the minimum processor requirements — it has enough RAM to run 10.5, but the installer prevents me from installing. I doubt I’ll be alone here,” ‘vorlonwarrior’ reports for macosxhints.

“All is not lost, however, as it is possible to modify the file that checks the machine specs and decides if 10.5 can be installed,” ‘vorlonwarrior’ reports.

The instructions are in the full article here.

MacDailyNews Take: It’s a bit of a convoluted process and not explained in enough detail as Terminal newbies might like, but, as our old (circa 1999) test Power Mac G4 (AGP) 450MHz, yes, 450MHz, with 1GB RAM, attests: it does work. Have you been successful with installing Leopard on unsupported Macs? If so, please, let us know how did you did it below.


  1. I just attached a a 533 mhz G4 in Firewire mode to my “approved G4” and installed Leopard on it that way, and it works just fine and actually, doesn’t seem to run any slower than Tiger did.

  2. Clever Torn8o,

    I wonder if I could hook up a G4 in Firewire Target mode to my Macbook? It probably wouldn’ t install the right software for the G4 hooked to an Intel Mac. Or does it always install a universal?

  3. I haven’ tried it yet, but what if I take the HD and install on an “approved” mac, install the OS then take that same drive and then install into an “unproved” mac?

    If the restriction only happens during install, would this still work? Or is there a restriction check at boot as well that needs to be reconfigured?


    Your annoying pop ads are even more annoying under leopard, as they jump up in separate spaces from the one safari is running in….

    MDN has lots of attitude but no style. This site is slow and badly designed.

  5. Just Don’t Do It.™

    If Apple has decided to forego the profits from a sale of a Leopard upgrade to you, it has undoubtedly done so because it would Suck Bad on your machine. The author says he has enough RAM to run Leopard, but so what? Is the GPU on his graphics card capable of running enough Core Image filters natively to give satisfactory performance in Spaces and Quartz Extreme? Does Core Video support GPU-accelerated codecs on that card?

    If you want to install Leopard on your legacy machine, and don’t care that your experience will probably be Really Really Bad, then go for it.

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