One of the requirements of Apple’s newly released Mountain Lion operating system is that it needs a certain level of Mac OS installed before you can upgrade to it, but what do you do if Apple no longer sells that step?

Users of slightly older Apple computers that want to upgrade to the latest version of Mac OS already have had to watch out for Apple’s minimum hardware requirement, but they now have a new issue to contend with.

Currently, only the following Apple computers can upgrade to 10.8 Mountain Lion:

  • iMac (mid-2007 or newer)
  • MacBook (late 2008 aluminium, or early 2009 or newer)
  • MacBook Pro (mid- or late 2007 or newer)
  • Xserve (early 2009)
  • MacBook Air (late 2008 or newer)
  • Mac mini (early 2009 or newer)
  • Mac Pro (early 2008 or newer)

Anyone with an older computer than those listed, can’t even make the attempt, with Apple requiring a new computer to make the transition.

But if you have an older iMac that is compatible from 2007 to mid-2009, there’s a possibility that your computer still has Mac OS X 10.5, also known as Leopard. That may have suited you fine for the past few years, but if you’re itching to upgrade, you now need a copy of an old operating system to upgrade.

According to Apple, the only way to update to the latest OS is through the Mac App Store, something that’s only available on 10.6.8, meaning it’s a two step process if you don’t have 10.6 already, forcing you to find and install Mac OS 10.6, install the updates, and then purchase and download 10.8 Mountain Lion.

That’s something that could be a bit of a problem, with Apple no longer selling Snow Leopard, the last version of Mac OS that Apple released on a DVD.

Snow Leopard: missing in action.

Several GadgetGuy readers have emailed us to ask what’s going on, and how they can upgrade, with Apple telling them to find copies of Mac OS X 10.6 Snow Leopard on trading services known for selling used copies, with Amazon and eBay both listed by Apple staffers.

There’s also another problem, as the suggestion by Apple’s workers that you buy a used copy of Snow Leopard actually goes against the software license agreement set forth by Apple, which states:

Subject to the terms and conditions of this License, unless you have purchased a Family Pack or Upgrade license for the Apple Software, you are granted a limited non-exclusive license to install, use and run one (1) copy of the Apple Software on a single Apple-branded computer at a time. You agree not to install, use or run the Apple Software on any non-Apple-branded computer, or to enable others to do so.

While the copy of Snow Leopard won’t be on computers for all that long before the machine is likely updated to Mountain Lion, it’s still against Apple’s own license agreement.

So now the catch is to find a new copy of the operating system, a task that seems about as difficult as it gets. Apple no longer stocks Snow Leopard, and our searches of regular electronics retailers JB HiFi and Dick Smith have come up with nothing, with searches of Apple Authorised Resellers leaving us in the exact same place.

Found a link from Snow Leopard on the Apple Store from Google? Here's where it goes.

It could be a situation where Apple is attempting a forced upgrade, a tactic we’ve seen from the company before when it no longer lets various devices update to new operating systems, as has certainly been the case with past generations of iPhones and older Mac computers.

Regardless, we’ve contacted Apple for more information about this issue, as well as how older Mac users can upgrade and where they can find Snow Leopard legally, and will update this story when Apple gets back to us.