Disables file previewers in Microsoft Office programs. This policy will not disable file previewers for Microsoft Windows. ...

Disables file previewers in Microsoft Office programs. This policy will not disable file previewers for Microsoft Windows.
      
To disable a file previewer, type the CLSID for the previewer you want to disable (the previewer CLSID can be found at HKLM\Software\Microsoft\Windows\CurrentVersion\PreviewHandlers).