The HKEY_LOCAL_MACHINE\SAM subtree contains the user and group account information in the Security Account Manager (SAM) database for the local computer. For a computer that is running Windows NT Server, this subtree also contains security information for the domain. This information is what you see in User Manager, and it also appears in the lists of users and groups when you use the Security menu commands in File Manager.
This subtree is mapped to HKEY_LOCAL_MACHINE\SECURITY\SAM, so changes made in one automatically appear in the other.
If you want to change user account or global group account information, use User Manager or User Manager For Domains to add or remove users or to change information about any account.
Caution
The information in this database is in binary format and should not be changed using Registry Editor. Errors in this database may prevent users from being able to log on to the computer—which is another reason why system administrators should not allow typical users to log on as members of the Administrator group.
System Administrators can use User Manager or User Manager For Domains to change security information for the local computer or for the domain.