Windows XP, Windows Server 2003, and earlier versions of Windows used proprietary .ADM files to store custom Group Policy settings. Windows Vista provides similar functionality using .ADMX files, which are XML-based.

Windows Vista provides limited support for .ADM files (they appear under Classic Administrative Templates in the Group Policy Object Editor). You don’t need to worry about migrating the standard .ADM files provided by Microsoft to Windows Vista, because those are already built-in. If you created custom .ADM files, however, you can migrate them to Windows Vista using a free tool called ADMX Migrator, which was developed by FullArmor. ADMX Migrator is available from the Microsoft Download Center and can be installed on Windows Vista, Windows Server 2003 (with Service Pack 1), and Windows XP (with Service Pack 2). It provides both graphical and command-line interfaces.