According to our research, Parallels is 28% more effective than VMWare Fusion at keeping the stench of Windows evil out of your Mac OS.  

“It’s well known that Windows exudes a certain amount of evil whenever it’s running,” said our lead testing ninja, “and you have to expect a certain amount of seepage. I mean, your Mac is sharing screen space, memory, audio channels, and everything else, so the Windows evil is soaking into your dock, your desktop picture, everything.”

Overall, we found that, after 100 hours of use, Fusion poured 250 units of evil into our test iMac, while only 180 units had spilled over from Parallels.  VirtualBox was tested, but we really didn’t care about the outcome.

“We think it has something to do with the way each system handles its desktop integration,” our ninjas report.  ”Parallels tries to contain elements in a simple ‘cohesion’, whereas Fusion seeks for real ‘unity’.”

Fortunately, there are ways that you can mitigate the effect of Windows evil when using virtualization technology.  The first, of course, is to always run Windows in “single window” mode, so that the virtualizer will wrap a protective Cocoa frame around Windows.  This also mitigates the evil spread by using a single mouse pointer between two operating systems.

“Never share cursors,” said Leo Laporte.  ”A contaminated cursor can carry corrupted drivers, dirty files, anything.  Be sure your cursor is free of Windows before use, every time.”

Other strong pollutants include Windows Media Player, Microsoft Office, and, of course, Internet Explorer.  

“Basically, running Microsoft products that have perfectly acceptable Mac counterparts degrades the moral shield inherent in OSX and allows a greater flow of evil.”

“Internet Explorer is evil,” said Douglas Adams, who came back from the dead to contribute to this article.

When asked about the effects of running Linux in virtual machines, our lab ninjas simply stared. “Linux. In a virtual machine. On a Mac.  Why?  Why would we do that?”

Apple declined to comment, but was seen buying some E-Z Cleen™ Evil Remover after seeing the test results.