Windows – Group Policy – Software Restrictions

This is by design. UAC strips the admin credential from any un-elevated process. If you're attempting to use an un-elevated process to access a remote share using only admin credentials, UAC will strip the admin credentials from the process' security token and the process will receive an "access denied" error.

To remedy this you can:

1. Don't use admin credentials to secure the folder (create a generic group just for this purpose), or

2. Disable UAC on the fileserver (not recommended), or

3. Enable the following registry key on the fileserver to disable just this portion of UAC.

More info: Description of User Account Control and remote restrictions in Windows Vista

GptTmpl.inf is where the security settings are stored, so if that file is not present that would explain why the settings were gone. Hard to determine who or what did this unless you have auditing enabled. Restoring the GPO from backup using Group Policy Management Console is preferred over re-creating it.

I would check the antivirus product to ensure it is excluding that folder (both the actual folder and the network path).

It's possible that if multiple persons are editing the same GPO at the same time, bad things can happen. If there is a conflict, it will appear under the following hidden folder:

C:\windows\sysvol_dfsr\domain\dfsrprivate\conflictanddeleted\

or

C:\windows\sysvol\domain\dfsrprivate\conflictanddeleted\

Use the following to clear the conflicts folder in SYSVOL:

http://blogs.technet.com/b/askds/archive/2008/10/06/manually-clearing-the-conflictanddeleted-folder-in-dfsr.aspx