ADMX File

What are ADMX files and how to open them

Are you having problems opening an ADMX file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your ADMX files.

What is an ADMX file?

An .ADMX file is a Group Policy Administrative Template file.

Group Policy Administrative Template files (.ADMX) are language-neutral XML documents used by Microsoft Windows starting with Windows Vista (Service Pack 1) to define registry-based policy settings. These files specify configuration options and UI labels for machine or user policies in Group Policy environments, separating policy definitions (.admx) from the localized language strings (.adml).

They are created by Microsoft (for the operating system and optional applications) or by third parties to describe new settings that administrators want to manage. Windows reads these files when rendering policy nodes in the Group Policy Editor, or when an MDM solution consumes them to present policy options. ADMX files are often stored locally under %SystemRoot%\PolicyDefinitions or centrally in a domain's SYSVOL "PolicyDefinitions" folder to be shared among multiple devices.

In the XML structure, each file begins with the declaration of policy namespaces, followed by policy definitions enclosed in elements such as <policies>, <policy>, with attributes like displayName, explainText, supportedOn, key and valueName specifying how the registry is affected. Keywords such as policyNamespaces, supportedOn, parentCategory, displayName, schemaVersion appear in their content. These byte-level signatures include strings like "MICROSOFT.POLICIES.", "POLICYDEFINITIONS", "SUPPORTEDON", "DISPLAYNAM", "SCHEMAVERSIO" among others.

How to open ADMX files

Important: Different programs may use files with the ADMX file extension for different purposes, so unless you are sure which format your ADMX file is, you may need to try a few different programs.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Last updated: August 17, 2026

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