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As Windows 7 comes with a virtual XP machine for backward compatibility i would really like to know why? I tried to bing a few papers what is not working anymore without luck.

I would assume that only some kind of system administration stuff is not working anymore and other programs are maybe just raising a few more security dialogs - but this is a shoot in the dark.

Please enlighten me.

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migrated from Aug 14 '09 at 16:42

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One thing to keep in mind is that Windows XP Mode will only be available with Windows 7 Ultimate and Business editions. It will not be available with Windows 7 Home Premium. As far as I know, unless they've changed it. – Chris Pietschmann Aug 16 '09 at 6:24
up vote 3 down vote accepted

Some possibilities:

  • Device drivers tied to WinXP (i.e. check OS version <= 5).
  • Application software that relies on WinXP bugs that have been fixed.
  • Applications for which it will cost too much to verify under Win7.
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Short answer: to ensure compatibility with 3rd party apps not made by MS.

  • business/marketing purposes (nearly 100% compatible with all current applications!)
  • make development of Windows OS easier (not as much need to explicity code for backwards compatibilty on case-by-case basis)

Longer answer:

Obviously, XPM has huge ramifications for Windows going forward. By removing the onus of legacy application compatibility from the OS, Microsoft can strip away deadwood technology from future versions of Windows at a speedier clip, because customers who need to run older applications can simply do so with XPM. For Windows 7 specifically, XPM is a huge convenience, especially for Microsoft's corporate customers, who can of course control XPM behavior via standard Microsoft administration and management technologies like Active Directory (AD) and Group Policy (GP). And it significantly recasts the Windows 7 compatibility picture. Before, Microsoft could claim that Windows 7 would be at least as compatible as Windows Vista. Now, they can claim almost complete Windows XP compatibility, or almost 100 percent compatibility with all currently running Windows applications.


Backwards compatibility is a huge, necessary burden for Microsoft. The XP virtual machine is a way to keep current XP users (mostly businesses) happy without stifling innovation and costs associated with maintaining backwards compatibility.

Microsoft must keep Windows compatible with previous versions otherwise current users will not upgrade. Users' 3rd party apps may be difficult, if not impossible to update for Windows 7. If their software does not run on Windows 7, it is a huge mark against it.

Besides being a pain for Microsoft developers, backwards compatibility also stifles innovation. Often backwards compatibility means Windows cannot be redesigned in a major, beneficial way. Raymond Chen describes it well: the cost of backwards compatibility is the design.

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