Share Windows XP license between Parallels and Boot Camp

posted in the wee hours by Constantinos. Filed under OS X, Windows

This post was originally published in 2007
The tips and techniques explained may be outdated.

Since my first installation of Boot Camp and Parallels, I’ve kept two separate Windows XP installations on my drive. One on Boot Camp, used for gaming and other resource-intensive tasks, and the other exclusively on Parallels, used for running some random software I come across and also to test the websites I build in IE. The reason I’ve been doing this is because even though Parallels touts being able to run a boot camped windows installation [via lifehacker], you can’t do BOTH (at least not off the shelf). You have a Boot Camp installation that you either run through Parallels, or by itself. The reason for this is that Parallels has to create a new hardware profile which XP picks up as a different machine, and invalidates your installation.

No matter how much I searched I couldn’t find a way to use the same installation under both circumstances. Thus, when Parallels 3 came out I immediately paid for the upgrade (even before the release) for the much promised ‘3D’ support, which, I believed, would enable me to play at least some of my games under Parallels, thus relatively eliminating the need to boot into XP. Alas, as most others, I was frustrated to find out that Parallels’ so-called 3D support was actually marginal support for DirectX 8.1, and absolutely NO support for DX9 or greater.

After all but giving up hope, I came across this comment on the afore-mentioned lifehacker post, which pointed me to a Parallels’ forum thread. To cut a long story short, I am now able to boot the same Boot Camp installation of XP both directly AND via Parallels without having WGA complain and invalidate my copy!

The process (reiterated from the above thread), is very simple:

  1. Find the MAC address of your Apples’s “en0” adaptor. To do that, either:
    • Open Terminal.app and type ifconfig en0, the MAC address should be located on the line that says “ether 00:00:00:00:00:00”, where ’00:00:00:00:00:00′ would be the code you’re looking for
    • OR open “System Preferences”, click on the “Network” icon, from the “show” drop down select “Built-in Ethernet”, click the “Ethernet” tab, and the MAC address should be listed under ‘Ethernet ID:’
  2. Start up Parallels and select your Boot Camp installation (do NOT start the virtual machine)
  3. Go to “Edit”/”Virtual Machine”
  4. Select “Network Adapter 1” on the left, and the “Advanced” tab on the right
  5. In the “MAC address” field replace the entry with the MAC address of en0 which you lifted above, minus the colons.


That’s it! No more complaining by that damned WGA 🙂

One Response to “Share Windows XP license between Parallels and Boot Camp”

  1. 1. Comment by K
    on 2007-08-05 @ 9.59 am · Quote #2011 ·

    Wow! I can’t wait to try this!!!

    Thanks a bunch!

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