ADMX - An appropriate resource file could not be found for

I had uninstalled some updates, and after that whenever I open gpedit.msc I will be greeted by this error message twice, the second time its font is black & bold.

I misundertood this first, thought it is because the file is not present, but it still has leftover registry entries(or some config files), and gpedit.msc is configured to open it when running, thus generating this error.

Turns out there is WindowsMediaDRM.admx but .\en-US\WindowsMediaDRM.adml is missing, what "An appropriate resource file" actually refers to, its vagueness caused my confusion.

I know it can be solved by copying the file from another computer, I don't want to do it, as all other computers I can access will cost my money...

My system is Windows 10 version 20H2, edition Windows Pro N for Workstations, 64 bit, OS Build 19042.631, Microsoft Docs:ADMX_WindowsMediaDRM says Pro isn't supported, I assume this means there should not be this WindowsMediaDRM.admx in %WINDIR%\PolicyDefinitions, but it actually should be present;

C:\WINDOWS\system32>dism /online /cleanup-image /restorehealth /source:E:\Sources\install.wim
Deployment Image Servicing and Management tool
Version: 10.0.19041.572
Image Version: 10.0.19042.631
[===========================84.9%================= ]
[==========================100.0%==========================] The restore operation completed successfully.
The operation completed successfully.
C:\WINDOWS\system32>sfc /scannow
Beginning system scan. This process will take some time.
Beginning verification phase of system scan.
Verification 100% complete.
Windows Resource Protection did not find any integrity violations.

The error persists... Because the Component Store(%windir%\WinSxs) contains only WindowsMediaDRM.admx and since it is present so nothing to be repaired, the missing file is C:\Windows\PolicyDefinitions\en-US\WindowsMediaDRM.adml and the file isn't contained in winsxs so it wasn't restored.

Simply installing "Administrative Templates (.admx) for Windows 10 October 2020 Update.msi" did not solve the problem, the error still persists, I tried to copy WindowsMediaDRM.admx from "C:\Program Files (x86)\Microsoft Group Policy\Windows 10 October 2020 Update (20H2)\PolicyDefinitions" to C:\Windows\PolicyDefinitions, and found the file to be present:

I had run dir commands to list files of the PolicyDefinitions folders:

%ProgramFiles(x86)%

C:\WINDOWS\system32>dir "C:\Program Files (x86)\Microsoft Group Policy\Windows 10 October 2020 Update (20H2)\PolicyDefinitions" /s /b | find /i "windowsmedia"
C:\Program Files (x86)\Microsoft Group Policy\Windows 10 October 2020 Update (20H2)\PolicyDefinitions\WindowsMediaDRM.admx
C:\Program Files (x86)\Microsoft Group Policy\Windows 10 October 2020 Update (20H2)\PolicyDefinitions\windowsmediaplayer.admx
......
C:\Program Files (x86)\Microsoft Group Policy\Windows 10 October 2020 Update (20H2)\PolicyDefinitions\en-US\WindowsMediaDRM.adml
C:\Program Files (x86)\Microsoft Group Policy\Windows 10 October 2020 Update (20H2)\PolicyDefinitions\en-US\windowsmediaplayer.adml
......

%windir%

C:\WINDOWS\system32>dir "C:\Windows\PolicyDefinitions" /s /b | find /i "windowsmedia"
C:\Windows\PolicyDefinitions\WindowsMediaDRM.admx

With the help of @Rambound I understood the cause of this and recognized my assumption as erroneous, I had solved it by simply copying the file at this path:

C:\Program Files (x86)\Microsoft Group Policy\Windows 10 October 2020 Update (20H2)\PolicyDefinitions\en-US\WindowsMediaDRM.adml

To this path:

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

I still don't understand why Windows always gives vague error messages, had the error message not be so vague but clear, I wouldn't be confused about its meaning and solve it right away...

1 Answer

I know it can be solved by copying the file from another computer, I don't want to do it, what registry keys or what .ini (I assume it to be .ini) files store which files gpedit.msc is configured to open so that I can delete the entry?

The error is caused by the existence of an .ADMX policy file, but the .ADML file for the policy file is missing, both files must exist for the policy to appear in the local group policy editor. Since you don't want to use another computer to resolve this error you can just install Administrative Templates (.admx) for Windows 10 October 2020 Update (20H2)

My system is Windows 10 version 20H2, edition Windows Pro N for Workstations, 64 bit, OS Build 19042.631, Microsoft Docs:ADMX_WindowsMediaDRM says Pro isn't supported, I assume this means there should not be this WindowsMediaDRM.admx in %WINDIR%\PolicyDefinitions, if that is true, then it would be really strange...

The documentation simply is indicating that the policy will not be enforced on Windows 10 Professional. The policy file most definitely is supposed to exist.

I was able to recreate the error myself on my virtual machine. I manually deleted WindowsMediaDRM.adml within the appropriate language folder (i.e. en-US) within C:\Windows\PolicyDefinitions\ and received the same error. I simply restored the file, from the contents of the suggested Administrative Templates file, and the error went away.

An alternative solution is to simply delete C:\Windows\PolicyDefinitions\WindowsMediaDRM.admx and it will likely be restored when the next feature update is installed. The .ADMX policy file is actually what makes the policy appear in the local group policy editor. In my testing I remove just the .ADMX and didn't initially receive an error.

As for the reason the DISM command didn't restore the file. Based on what I can tell WinSxS only contains WindowsMediaDRM.admx, since the file exists, there were no files to restore. WinSxS is the directory used to repair a Windows installation, when the image on the system (i.e. WinSxS), is corrupted and is contained within E:\Sources\install.wim