If you step away from your computer, you may want your Macintosh to log out automatically after a certain amount of time in which no activity (that is, no mouse clicks or typing at the keyboard) has occurred.
Ideally, you should make the inactivity time period short—say, 10 or 15 minutes. But don't make it too short: If you define too short a time, you could be reading on screen and your Macintosh may suddenly log you out because you're not typing or clicking.
By the same token, don't set the inactivity time too long, because that may give someone time to access your account while you've stepped away. Here's how to make your Macintosh log out automatically:
Click the Apple menu and choose System Preferences. The System Preferences window appears.
Click the Security icon under the Personal category. The Security window appears.
Click the General tab to view the General options.
Click the lock icon in the bottom-left corner of the Security window. (Skip this step if the lock icon already appears opened.) When a dialog appears, type your password and click OK.
Select the Log out after ___ minutes of inactivity checkbox (see Figure 52-1).
Click in the Log out after text box and type a number such as 8 or 15 to define how many minutes to wait before logging out automatically.
Click the close button of the Security window.