Contains information about users and groups associated with the computer. The SAM file found in local machines, on Windows NT and 2000, contains information about that specific machine, and only that machine. A machine that is connected to the network may have tow default accounts in the local SAM file, even if 10 different persons have logged onto it. The network logon process requires that users authenticate the user names and passwords through the domain sever. When a person logs onto a workstation computer, the information is sent to the domain server where it is authenticated. IF the authentication passes, the server sends a message back to the computer, which allows the logon to occur.