How to make iMac lock itself if left for 2 minutes?
If you follow the below 2 steps, you can set your machine to require a password after 2 minutes of inactivity.


Within the Desktop &amp; Screen Saver System Preference, set the screen saver to come on after 2 minutes of inactivity.
Within the Security &amp; Privacy System Preference, set the option to require a password immediately after sleep or screen saver begins.