Quickie: Get Group Policy Preferences to Reapply

Group Policy Preferences are great.  It's nice to pre-set things for your users and know they can change it if they have a need. 

This is a PITA to test though, as you can't re-apply the preference to your test machine. 

Here's the fix.

Open up the regkeys
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Group Policy\Client\RunOnce 
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Group Policy\Client\RunOnce

The GUIDs of the applied GPOs will be recorded here.  Delete them and reboot.  Viola, your GPPs will reapply like magic.