Search notes:

%CommonProgramFiles(x86)%

The default location for %CommonProgramFiles(x86)% seems to be C:\Program Files (x86)\Common Files.

See also

CommonFilesDir (x86) under the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
CommonFilesDir under HKEY_LOCAL_MACHINE\SOFTWARE\WOW643Node\Microsoft\Windows\CurrentVersion
%CommonProgramFiles%
%ProgramFiles(x86)%
The .NET enumeration System.Environment+SpecialFolder.

Index