When you view NTFS or share permissions, no account or group information is displayed, just the SID?
You Application event log contains:
Event Source: Userenv
Event Category: None
Event ID: 1000
Description: Windows cannot determine the user or computer name. Return value (5).</b>
This problem can be caused by removing the right to Access this Computer from the Network from the Everyone and/or Authenticated Users group.
To fix the problem, insure that Administrators, Authenticated Users, and Everyone has the right to Access this Computer from the Network.
NOTE: Include the Everyone group because some operations involve accounts that have NOT been authenticated to the domain, such as when a user changes an expired password, or in dealing with trusts.
Use the appropriate GPO and navigate through Computer Configuration\Windows Settings\Security Settings\Local Policies\User Rights Assignment.