Whether you’re at home or at work, you might not want other people snooping on your Mac when you step away. Leaving your Mac unlocked and unattended allows others nearby to read your emails, text messages, browser history, and all your files. You may be researching gifts for your family, or you may be working on a project in your office that is for your eyes only. In any of these cases, when you step away from your Mac — whether for a meeting or to go make a cup of coffee — it’s a good idea to lock your Mac screen.
You don’t need to shut down your Mac, you don’t even need to log out. There are several ways you can quickly lock your screen and protect your Mac from prying eyes, so no one can access your data without entering your password. It only takes a second, and a keypress or a swipe of your mouse, so it’s worth learning how to do this.
Read the rest of the article on The Mac Security Blog.