On this OS 10.9 computer, the display icon is not in the menu bar OR doesn’t have the option to turn on mirroring OR appears twice
The system often will not show the Display icon in the menubar even when you have an external display connected (a problem since Mac OS X 10.8). If you are having that problem, you can use the Display Menu application instead, which is located in the Applications folder on staff computers. Display Menu is already configured to load and appear in the menubar for all staff on computers running Mac OS X 10.9. If it does not appear, here's how you can add it to the menubar:
Note: If you are using an Apple TV in your classroom, Display Menu will not work properly and should not be installed on the computer that uses Apple TV.
1. Navigate to your Applications folder in a finder window and double click on Display Menu.
2. The Display Menu icon will appear in the Finder menubar. Click and hold on the icon to reveal the drop down menu. Select Start on Login from the drop down menu. The Display Menu icon will then appear in the Finder menubar each time you log in to your computer.
The most stable resolution when connected to a projector or other display is 1024 x 768. More details about resolution choices are available in KB article #239.