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Parallels' users can ask Ben anything

Continuing our report of "Ask Ben Anything", quoted from Ben Rudolph's Parallels Blog Site, Parallels users write in to get their questions answered about the product or the market in general:

If I want the option of running Windows XP under both Parallels or Boot
Camp. What are the Windows license implications? Must I purchase two
copies of Windows XP? (It seems that since it is on the same hardware
and not running concurrently, that a single license for Windows should
be sufficient, at least in the legal sense). Will Microsoft allow the
same copy of Windows to be registered for both Parallels and Boot Camp?

- Clinton W.

The best answer I can give is "maybe". There are a lot of versions of Windows out there, and the EULA (End User License Agreement) can be slightly different in each. In most cases, the EULA states that Windows XP can be installed on one machine, which can be interpreted in two ways:

  1. You need need two licensed copies of Windows to use both Parallels and Boot Camp at the same time.
  2. Since Parallels and Boot Camp reside on the same machine, you're good to go.

I have heard that many of our users have had success with interpretation #2 by calling Microsoft and explaining that they're planning on using the same copy twice on one machine, and that Microsoft has said OK. Your results may vary.

This issue with multi-machine licensig becomes much more concrete when it comes to Vista. Microsoft just announced that VistaVista Home Basic and Vista Home Premium in a virtual machine, via the rather direct statement "You may not use the software installed on the licensed device within a virtual (or otherwise emulated) hardware system,". You can, however, install Vista Ultimate and Vista Business, in any virtual machine. For the entire Vista license agreement, check out the EULA section of Greg Kezier of TechWeb also wrote a good article on the new EULA changes, which you can read here.

The bottom line when installing XP or any Windows OS is make sure that you've ready your copy's EULA, and that you abide by it, or else its entirely possible you get a nastygram from Microsoft Legal telling you that you're operating your machine illegally, and that you owe them some money.

Hi Ben-

The FAQ suggests downloading a trial version and trying it out, when my favorite OS is not listed in the supported Guest OS's list. But I'm too busy and lazy to try that, so I'll ask you instead: what about various versions of Mac OS X itself as a Guest OS for 'Parallels Desktop for Mac'? Can you do that?

Hmmm, would this allow you to test the Mac OS X-compatibility of new development versions of 'Parallels Desktop for Mac' itself, using a stable version of Parallels running different Mac OS X versions each running the new version inside, each runnning various other OSes? The mind reels....

Chris K.

While this is technically possible, running OS X in a virtual machine is a clear violation of Apple's OS X EULA, which states in Section 2, subsection A: "
This License allows you to install and use one copy of the Apple Software on a single Apple-labeled computer at a time. 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. "

So, in order for us to make this happen, we need Apple to give us the green light, which they have so far been reluctant to do. If you want to see this happen (I know I do), let Apple know by filling out their feedback form on

As for running a virtual machine via Parallels Workstation in a Windows virtual machine running in Parallels on a Mac (wrap your head around that one), this IS possible...just don't expect amazing performance, since you're effectively working in a virtual machine running in a virtual machine running on real hardware.

Thanks for the question...I feel dizzy now...

Hi Ben,

Any idea when Parallels for Win/Linux is going to support a 64-bit host OS? The FAQ says you need a 32-bit host OS in 2.1 but it says 64-bit host support is in the plans. The 2.2 release notes mention support for AMD virtualization technologies but no mention of 64-bit host support. I currently dual-boot between Windows XP-Pro 64 and SuSE-64 on an AMD FX-2 chip. I'd like to move to virtualization and run Vista-64, RedHat, etc. as well.

Ramin F.

Full 64-bit support for both primary and guest operating systems is planned for the next version of both Parallels Workstation and Parallels Desktop. These new, improved versions should drop in beta sometime around the turn of the year. We know that there are a lot of people running 64-bit chips in PCs, and that Macs will be moving to all 64-bit soon, so we're working as hard as we can to make our stuff able to take full advantage of the new chips!


The original can be found here.  Ask Ben your questions.

Published Sunday, October 22, 2006 9:30 PM by David Marshall
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