Fixing ADMX Import Error in Intune: "NamespaceMissing:Microsoft.Policies.Windows"

When you try to import an ADMX file into Intune, you may encounter this error:

ADMX file referenced not found NamespaceMissing:Microsoft.Policies.Windows. Please upload it first.

Understanding the error message

The NamespaceMissing error commonly occurs when an ADMX file references another namespace defined in a separate file—often Windows.admx, which contains core Windows policy settings.

This message indicates that the ADMX file you're trying to import depends on another ADMX file that hasn't been imported yet.

A common example: the OneDrive.admx file requires Microsoft.Policies.Windows to function. If this dependency is missing, the import will fail.

<policyDefinitions xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" revision="1.0" schemaVersion="1.0" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
  <policyNamespaces>
    <target prefix="OneDriveNGSC" namespace="Microsoft.Policies.OneDriveNGSC" />
    <using prefix="windows" namespace="Microsoft.Policies.Windows" />
  </policyNamespaces>

Get the missing file

For Windows-related ADMX files, you can find them locally on a Windows machine.
The typical path for ADMX files (such as Windows.admx) is:

C:\Windows\PolicyDefinitions\Windows.admx

And the associated ADML file:

C:\Windows\PolicyDefinitions\en-US\Windows.adml

Importer les fichiers dans l’ordre

1. First, import the Windows.admx file and its associated en-US ADML file into Intune.
2. Then, import the dependent file (such as OneDrive.admx).