If I upgrade my Snow Leopard to Lion, is it technically and legally possible to reinstall the original Snow Leopard into a virtual machine, which is inside the same, original, Apple-branded iMac?

From the Snow Leopard software license agreement §2. Permitted License Uses and Restrictions:

A. Single Use License. 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. This License does not allow the Apple Software to exist on more than one computer at a time, and you may not make the Apple Software available over a network where it could be used by multiple computers at the same time.

It would seem to me* that there's nothing wrong: the working operating system is Lion (not Snow Leopard), so I would enable only one copy of Snow Leopard to run. The virtualization software is running under Apple-branded computer. Right?

Is it technically possible?

*) iANAL

  • I think Snow Leopard virtualized on Snow Leopard was only (legally) possible for Snow Leopard Server. I guess that still holds, since the license for Snow Leopard has not changed.
    – Thilo
    Commented Jul 23, 2011 at 9:31
  • @Thilo But the question is virtualizing Snow Leopard on Lion. Where did that clause originate, anyway? The SL's license doesn't have word/part-word server or virtual in it. Commented Jul 23, 2011 at 9:56

2 Answers 2


Yes - it is technically possible.

The Leopard and Snow Leopard installers look for a file (even if it's empty) named /System/Library/CoreServices/ServerVersion.plist

Armed with this, you should be able to search for many "how-to" articles like this.

Be aware, the comments on the page call out issues that this "hack" causes when running the OS (software updates is confused by this file's presence/absence)

Legal and moral issues aside. (I'm not a lawyer but I too fail to see how the license prevents you from virtualizing your legally purchased Snow Leopard on a legally purchased Mid 2011 MacBook Air)

Think of this as an iOS jailbreak - someone has to stay on top of the things that these changes break, but the payoff may be well worth the hassle.

  • (and it goes without saying - if you have to modify or reverse engineer the product, that's also against the licensing terms)
    – bmike
    Commented Jul 25, 2011 at 17:20
  • 1
    And if you’re trying to run a retail copy of 10.6 in VMWare Fusion 3.1.3 on Mac OS X Lion, you definitely shouldn’t scroll down to this comment, because the steps it suggests are probably against the 10.6 license agreement. Commented Aug 15, 2011 at 21:42

According to §3 Transfer, if you've upgraded you're not permitted to continue using the older release:

If an Apple Software update completely replaces (full install) a previously licensed version of the Apple Software, you may not use both versions of the Apple Software at the same time nor may you transfer them separately.

  • Ah, but it isn't the Apple Software update which updates the Snow Leopard—it's the Mac App Store. I think this is to prevent using e.g. 10.6.8 as primary OS and 10.6.7 as a virtual machine. Commented Jul 26, 2011 at 12:50
  • Hmm... My reading is that it's an update from Apple Software, not an update via Software Update (note the capitalisation as well as the term full install). I interpret that as meaning "if you've upgraded from Leopard to Snow Leopard, you can't keep using Leopard or sell it to anyone without selling them Snow Leopard too". Of course, IANAL...
    – mjturner
    Commented Aug 12, 2011 at 9:03

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