I was asked by a customer, or rather a colleague of mine took the query who passed it on to me, how you could use group policy to affect the Windows Explorer setting to hide file extensions for known file types. This isn't a setting which is directly exposed by group policy through one of the standard administrative templates.

Hence, what better way to show the example than through a blogcast. The blogcast demonstrates some important concepts.

• If there is a registry setting being changed through Windows Explorer, you need to locate it. Yes, you can use many Internet sites, but why not find it out yourself - I show you how.
• You need to craft a custom administrative template - I show an example.
• You need to scratch your head for a while when you find that a setting which isn't "True Policy" isn't displayed by default in the Group Policy Object Editor.

The link to the blogcast is here  - it's just under 8 minutes and just under 3MB in size. Happy viewing.

By the way, here's the custom ADM file I used to save you re-typing it.

CLASS USER
CATEGORY "Hide File Extensions"
 POLICY "Hide file extensions"
  KEYNAME "Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced"
   VALUENAME "HideFileExt"
   VALUEON NUMERIC 1
   VALUEOFF NUMERIC 0
 END POLICY
END CATEGORY