Enabling Function Keys on Portable Macintosh Computers
By default, on MacBook and MacBook Pro computers, the F1–F12 keys are assigned to
hardware controls, such as brightness, audio volume, numlock, and so on. Therefore, you
must press the Function (Fn) key with the F-key to invoke F-key commands in software
You can change keyboard preferences so the F-keys work in the traditional manner,
without pressing the Fn key. When this setting is activated, you can press the Fn key with
the F-key to activate the hardware commands.
To enable traditional function keys
In the Keyboard tab of the Keyboard & Mouse preferences in System Preferences, select
the “Use all F1, F2, etc. keys as standard function keys” checkbox. Uncheck the box to
return to the default setting.