Configuration file used by Windows Group Policy, a software technology used to manage groups of computers; contains settings for user accounts, operating system configurations, and applications; used for storing configurations for the centralized management of many computer systems.

ADMX files control what users are capable of doing on their computer. For example, an ADMX file in a work environment may restrict access to the Internet or downloading certain types of files. Windows 7 administrators can access local policies using the Local Group Policy Editor MMC snap-in (.MSC file), which is named gpedit.msc and is located in the \Windows\System32\ directory. Windows Group Policy is often setup with Active Directory, a permissions manager. It can also work with other supporting permissions technologies. ADMX files can be exported to a tab-delimited text file using the ADM File Parser (AdmX) command-line tool. The tool is included with the Windows Server 2003 Resource Kit Tools package. NOTE: ADMX files were introduced with Windows Vista and Windows Server 2008.