If you add contact information to the login screen, anyone who boots your Mac will know how to contact you; that’s especially useful if you own a MacBook. While you’re logged in as an administrator, launch Terminal (in /Applications/Utilities). Type sudo defaults write /Library/Preferences/com.apple.loginwindow LoginwindowText -string “yourtexthere” – whatever you want to appear on the login screen should be inserted in place of yourtexthere. (For example: ‘Reward if returned: [email protected] or 01234 123456.’) Press Return, and then (when prompted) provide the administrator password and press Return again.