In the Account Manager, select a user name, then select Login Controls from the Users menu.
To lock an account, click on the Lock Account button. When an account has been locked, the Unlock Account button appears instead.
If a lock has been applied to the account, it is listed under ``Current Account Lock Status''. An account can be locked because:
You can also unlock accounts from the command line:
passwd -u username
To lock an account, use the -l option.