Enable Classic Shell
User Configuration\Administrative Templates\Windows Components\Windows Explorer
Disables Active Desktop, Web view, and thumbnail views. Also, users cannot configure their system to open items by single-clicking (such as in Mouse in Control Panel). As a result, the user interface looks and operates like the interface for Windows NT 4.0 and users cannot restore the new features.
This policy takes precedence over the Enable Active Desktop policy. If both policies are enabled, Active Desktop is disabled.