OS X Lion: Turn your screen saver on or off
If you use a screen saver, it starts automatically after your computer is inactive for a time. You can also choose a shortcut so your screen saver starts when you move the pointer to a corner of the screen.
- Choose Apple menu > System Preferences, click Desktop & Screen Saver, and then click Screen Saver.
- Click Hot Corners.
- Choose Start Screen Saver or Disable Screen Saver from the pop-up menu for a corner you want to use; and then click OK.
To use the Command (⌘), Control (^), Option (⌥), or Shift (⇧) key together with a hot corner, press the key while the pop-up menu is open. For example, if you press the Shift key, the Start Screen Saver command changes to ⇧-Start Screen Saver.
To deactivate the screen saver and return to the desktop, press any key, move the mouse, or touch the trackpad. If your screen saver is a slideshow, press the Spacebar to pause and resume.
You can lock your screen by requiring a password to turn off a screen saver.