MAC TIP: Choose the screen for an LCD Projector and MacBook


Drag the white bar at the top of the screens to the one you want to be the main screen. 

Apple icon >> System Preferences >> Displays >> Arrangement

When projecting a slide presentation you want the white bar on the display that is the LCD projector screen. The display without the bar will show your notes. (Detailed instructions are below the image.)



These instructions are the same for either connecting an external monitor/display screen to your computer or connecting a your computer to an LCD projector.

The computer essentially “sees” the projector as an external monitor.

Dual Display or Presentation Mode is where the two screens show two different things.

The most common use in regards to an LCD projector is when you want to view your “Presenter Notes” in either Keynote or Powerpoint on your laptop display and want the actual presentation – the slides or video – to be projected up on the screen for the audience.


  • Click the Apple icon in the upper-left corner of your MacBook Pro’s screen, then click “System Preferences.”
  • In the System Preferences window select “Displays”
  • If a picture similar to the one above does not show up, your computer may not be “seeing” the projector or external monitor. Click on “Detect Displays”.


  1. If the second display does not show up there is some problem with the cable connection.
  2. Recheck the cable for connectivity at each connection and try again.
  3. If that fails, rebooting will sometimes be necessary for the computer to pick up the projector.
  • Drag the white bar on the top of the display image to the display you want to use as the main display:

– When sitting at a desk with multiple screens, the screen with the white bar will be your primary screen.
– When using a projector, the screen with the white bar will show your presentation while the second screen will show your presenter notes.

  • To rearrange the screens simply drag them to the position you want them to be in. (This is important if you are going to be using the mouse on both screens.)
  • Or if you want to show the same image on both screens, select “Mirror Displays” and the white bar will disappear.

Mirroring, is what the MacBook will often default to. It will show the same identical information on both your computer and on the projector screen.