Note: Make sure you have a Backup of the security permissions before revoking permissions.
To revoke all permissions on unknown accounts
1 Open the module for the type of permission you want to revoke.
2 Open the Browse tab.
3 Select an item in the Navigation pane OR Type a path in the Path box, and click Go.
4 Select Advanced Revoke Options.
5 Click Yes.
6 Select Revoke all unknown and deleted accounts.
7 Click OK. The Revoking Permissions box displays the progress.