The Registry client-side extension is responsible for writing and removing registry keys and values from the client's registry during Group Policy processing.
Correct a registry extension failure
The Registry client-side extension failed to read the registry.pol file from the Group Policy template location. The registry.pol file contains registry policy settings. This file may be missing, inaccessible, or corrupt.
Possible resolutions include:
Ensure the registry.pol file exists in the location and has the same permissions as the gpt.ini file in the same Group Policy object (GPO).
Ensure Sysvol replication is working properly on domain controllers.
Delete the GPO and recreate it.