Guides Mac Tips

How to Lock Your Mac’s Computer Screen

Each of my two teenage daughters has her own MacBook, and they would like to lock their computer screens to prevent their machines from being used without their permission by other kids at school (and each other). Is there some software I can purchase to make this happen?
No need to purchase anything — this functionality is built right into your Mac. Two system preferences need to be adjusted in order for your children to protect their computers from prying eyes and fingers. First, go to System Preferences > Security > General, and select “Require password immediately after sleep or screen saver begins.”
Next, go to System Preferences > Desktop & Screen Saver, click the Screen Saver tab, and then click the Hot Corners button. Decide which corner of your screen you’d like to use for screen locking, then click the corresponding pop-up menu and choose “Start Screen Saver” or “Put Display to Sleep,” and click OK.
All those checkmarks mean that we’ve really beefed up our security!
To lock the screen, just move your mouse into that corner of the screen, and you’ll trigger the screen saver (or put the display to sleep). The computer is now locked, and it will require a password to get back in again.
For extra security, you may want to require a password when the computer starts up as well. Go back to System Preferences > Security > General, and select “Disable automatic login.”
Note that these steps will keep casual snoopers away from these machines, but it won’t stop an IT professional or an expert Mac user from infiltrating this security. For a more advanced layer of security, read Apple’s support article on setting an open firmware password atsupport.apple.com/kb/ht1352.