The internal version number for Windows Vista is 6.0. The GetVersion function returns this version number. The problem is, some applications will return a higher version number. This means trouble. Learn how to steer clear, here.

Symptoms of OS Version

• Applications that check for OS version will get higher version number.
• Application installers may prevent themselves from installing the app and apps may prevent themselves from starting.
• Applications may warn users and continue to function properly.

Mitigation Techniques for OS Version

• For apps and installers that check for OS version, a Compatibility mode is provided in Windows Vista
• Users can right right-click the shortcut or the EXE and apply the Windows XP SP2 compatibility mode from the Compatibility tab. This applies multiple shims including "WinXPSP2VersionLie"
• Better: Apply the shim "WinXPSP2VersionLie"
• In many cases, applications will work the same way that it did in Windows XP and there is no need for changes to the application

Fixes for OS Version

Applications should not perform version checks for equality (== 5.1)

• If you need a specific feature, check whether the feature is available.
• If you need Windows XP, check for Windows XP or later (>= 5.1).
• Exceptions to this occur when there is a very specific business, or legal need to do a version check, such as a regulatory body requires you to certify your application for each operating system and version.