ADMX Technology Review

Administrative Template files contain markup language that is used to describe registry-based Group Policy. First released in Windows NT 4, Administrative Template files used a unique file format known as ADM files. In Windows Vista, these files are replaced by an XML-based file format known as ADMX files. These new Administrative Template files make it easier to manage registry-based policy settings in Windows Vista and Windows Server 2008.

In Windows Vista, ADMX files are divided into language-neutral (.admx files) and language-specific resources (.adml files), available to all Group Policy administrators. These factors allow Group Policy tools to adjust their UI according to the administrator's configured language. Adding a new language to a set of policy definitions is achieved by ensuring that the language-specific resource file is available.

Comparison of ADM and ADMX Local File Locations

In Windows Vista, the operating system–defined Administrative Template policy settings will install only on the local computer as an ADMX file format.

ADMX files will be installed locally on a Windows Vista computer in a different file location from ADM files, as shown in the following table. (Custom ADM files can still be copied to the listed ADM directory to be consumed by Group Policy Object Editor and Group Policy Management Console.)

File Type File Location



ADMX language neutral (.admx)


ADMX language specific (.adml)

%systemroot%\policyDefinitions\[MUIculture] (for example, the United States English ADMX language-specific file will be stored in %systemroot%\policyDefinitions\en-us)

ADMX Domain File Locations

One of the main benefits of using the new ADMX files is the central store, available to you when you are administering domain-based Group Policy objects (GPOs). The design of the central store and the new way that GPOs store files greatly reduces the amount of storage space required to maintain GPOs. In Windows Vista and Windows Server 2008, Group Policy Object Editor will not copy ADM files to each edited GPO, which was the case with earlier operating systems. Nor will Group Policy Object Editor copy the new ADMX files. Instead, it will provide the ability to read from a single domain-level location on the domain controller's sysvol (not user configurable). If the central store is unavailable, Group Policy Object Editor will read from the local administrative workstation.

Note that the central store is not available by default -- you will need to create it manually, as described in Scenario 2: Editing Domain-Based GPOs using ADMX Files.

In addition to storing the ADMX files shipped in the operating system in the central store, you can share a custom ADMX file by copying the file to the central store. This makes it available automatically to all Group Policy administrators in a domain. Locations for ADMX files on domain controllers are shown in the following table.

File Type Domain Controller File Locations

ADMX language neutral (.admx)


ADMX language specific (.adml)

%systemroot%\sysvol\domain\policies\PolicyDefinitions\[MUIculture] (for example, the United States English ADMX language-specific file will be stored in %systemroot%\sysvol\domain\policies\PolicyDefinitions\en-us)


The Domain Controller file locations for the table assume you are logged onto one of the Domain Controllers for your domain.