PolicyDefinitions C:\Windows\PolicyDefinitions

PolicyDefinitions: ADMX files (language-neutral administrative templates) and ADML files (per-language text) read by this computer's Group Policy editor.

Updated on 12 November 2026 By AltF4 Formation

What it’s for

The local Group Policy editor (gpedit.msc) and the Group Policy Management console read the setting definitions of the “Administrative Templates” node from here. Each Windows version ships its new ADMX files with feature updates, which is why a recent client offers settings that an older server does not.

In a domain, the console prefers the SYSVOL Central Store (Policies\PolicyDefinitions) when it exists. Otherwise it falls back to this folder, on the machine running the editor.

What it contains

One .admx file per component (WindowsUpdate.admx, TerminalServer.admx, inetres.admx…). The XML is language-independent and describes the Registry key and value each setting writes.
One subfolder per language (en-US, fr-FR) with the .adml files, which hold labels and help text.
Third-party ADMX files (browsers, office suites) that you drop in to see them locally.

Risks and best practices

This folder is the source to copy when you feed the Central Store: take it from the most recent Windows you manage, language subfolders included.
An .admx without its .adml in the editor’s language triggers a load error in the GPO console.
Do not edit the files shipped with Windows; updates replace them. Third-party ADMX files belong in the Central Store.

Useful commands

# Number of ADMX templates and available languages
(Get-ChildItem "$env:windir\PolicyDefinitions" -Filter *.admx).Count
Get-ChildItem "$env:windir\PolicyDefinitions" -Directory | Select-Object Name

# Does the domain have a Central Store?
Test-Path "\\$env:USERDNSDOMAIN\SYSVOL\$env:USERDNSDOMAIN\Policies\PolicyDefinitions"

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