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Choosing a Windows 8 version for your Mac

If you're installing Windows 8 on your Mac, you need to make sure you have the right version. The wrong version of Windows 8 may not install in Apple's Boot Camp or in virtualization software such as Parallels Desktop or VMware Fusion. Or you may be buying a version that is more than you need.

With Windows 8, Microsoft changed the way it sells its OS. For one, it reduced the number of retail versions to two main types: regular and Professional. But there are actually four versions, because regular and Professional each come in two flavors: "Windows 8 Upgrade" and something called "Windows 8 System Builder OEM." Here are the four versions, with pricing from Amazon:

I'll get to the regular versus Pro in a minute. The more important choice is Upgrade vs. System Builder.

Windows 8 Upgrade is about $50 or so less expensive than System Builder, but only installs on an existing version of Windows 7, Vista, or Windows XP. It will also install on top of the old Windows 8 Preview, which expired in December of last year. If you upgrade from Windows 7, Windows 8 retains the software applications you have. Upgrading XP to Windows 8 only saves your files; upgrading from Vista saves files and settings as well.

Windows 8 Upgrade will not work if you're creating a brand new installation of Windows 8 in Boot Camp, or are creating new virtual machine with Parallels Desktop, VMWare Fusion, or Oracle VirtualBox. For these situations, you need a Windows 8 System Builder OEM version. The term "System Builder" refers to people who build their own PC from parts. Creating a new virtual machine or a Boot Camp partition is the equivalent of building your own system.

But even if you already have a Windows 7 virtual machine, you may not want to convert it to Windows 8. Consider using System Builder to create a new Windows 8 virtual machine while retaining your old Windows 7 VM. Having multiple OS's installed at the same time is one advantage of virtual machines over Boot Camp.

You may be tempted to make a copy of a Windows 7 virtual machine, and run the less expensive Windows 8 Upgrade on one of the copies. The problem with this is that copying a virtual machine can cause Windows in the copied VM to ask you to activate it--which you may not be able to do if you've already activated this copy of Windows. Windows will do this because copying a virtual machine creates gives the copy a new MAC address, which is a unique identifier to a computer's (or virtual machine's) Ethernet connection.

Finally, you need to decide between the regular and Professional versions of Windows 8. The Professional version has features for enterprise networks. Windows 8 Pro adds the ability to be part of a Windows Active Directory domain and be controlled by group policies. Windows 8 Pro can also be controlled by Remote Desktop, includes an encrypted file system (called BitLocker), and can run virtual machines (called Hyper-V).

There are two other versions you don't have to worry about. Windows 8 RT is a version specially made for tablets with an ARM processor, including Microsoft's Surface Pro. RT won't run on your Mac. Windows 8 Enterprise is for organizations that have Microsoft Software Assurance agreements.