|Tip 227||Secure Your Mac by Locking It|
You can set your Mac to show a blank screen or start the screensaver on demand. If you also set a password prompt to appear when the mouse is moved or a key pressed, you’re effectively making the computer impossible to use until you return. Additionally, nobody will be able to see your screen contents as they pass.
Enabling Password-Protected Sleep
For screen locking to be effective, you’ll need to first activate password protection: open System Preferences (Apple menu→System Preferences) and click the Security & Privacy icon. Ensure the General tab is selected and then set Immediately in the drop-down list alongside Require Password.
Locking via a Keyboard Shortcut
To lock the screen quickly from the keyboard, hit Shift and Control together, and hit the Eject key (top right of the keyboard or top right of the main keyboard area on aluminum keyboards).
On a MacBook Air or Retina-enabled MacBook Pro, you can hit the power button instead of Eject, while still holding down Shift and Control.
Locking via a Menu Icon
A little-known way to lock the screen is to use a feature of your Mac’s Keychain Access application, which ordinarily handles password and certificate security for your Mac. Start the application (open Finder, select the Applications list, and then double-click Keychain Access within the Utilities folder), and select Preferences from the application menu. After ensuring the General tab is selected in the dialog box that appears, put a check next to Show Keychain Status in Menu Bar.
You’ll now see a padlock icon appear at the top right of the screen near the time display (you can now quit Keychain Access because we’re finished with it). Clicking the padlock will show a menu with a Lock Screen menu option.
To remove the padlock icon later, hold down Command and simply drag the icon onto the desktop. Upon releasing the mouse button, it will disappear.
Locking via Touching a Screen Corner
You can also set up your Mac so that pushing the mouse cursor into a particular corner of the screen activates sleep mode. To set this up, start System Preferences (Apple menu→System Preferences), click the Mission Control button, and then click the Hot Corners button. Click the drop-down list next to whichever corner(s) you’d like to use and select either Put Display to Sleep or Start Screen Saver, if you don’t want to leave the screen black. Then click the OK button.