How to Instantly Lock your Mac OS X Screen in Lion

Please Note: Click here for the updated blog post for Instantly Locking your Screen in Mavericks.
One of the most common questions I’m asked by Mac users is how to quickly lock the screen when needing to walk away from your desk and leave your computer.
The easiest and quickest way to lock a Mac OS X screen is to use the keyboard shortcut of holding down the Control+Shift+Eject keys together.
When you press these keys together, your Mac display screen will go black and lock the Mac screen, requiring a user to enter their user account password before the Mac can be used again, providing you have this setting enabled. (Essentially, these keys execute two commands. Firstly, they turn off the display lamp, then they optionally start the lockscreen facility).
If you do not have the password required feature enabled, then follow these simple steps to set this up on any Mac:

  1. Launch System Preferences.
  2. Open the “Security & Privacy” preference pane and select the “General” tab.
  3. Click the checkbox next to “Require password after sleep and screen saver” – you can select either immediately or a preferred time interval.
  4. Close System Preferences and you’re done!
How to Instantly Lock your Mac OS X Screen in Lion

This feature is a great option to enable in environments where you may have sensitive data on your Mac that you want to ensure is not accessible when you leave your Mac powered on.
This feature has been tested using Mac OS X v10.7.4 which was the latest Mac OS release at the time of writing and also using the latest internal and external Apple keyboards.