How to Extend the Desktop Over Two Monitors on a Mac

By David Perez

While small computer monitors save space and offer the convenience of portability, they tend to bunch up application windows and clutter the desktop. Utilizing two monitors effectively doubles the size of your workspace. If you need to use multiple applications at once, spreading them over two desktops will allow you to make your windows larger while helping to keep them organized.

Things You'll Need

  • Mac computer
  • Second Mac monitor or television with an RCA, S-Cable, VGA, Mini Display port or any DVI-style input

Step 1

Determine your Mac computer's type of display output. On desktops, these are usually located on the back panel, whereas laptops house them on the side of the machine. If the port has three rows each consisting of eight holes, it is DVI. If it has two rows consisting of eight slots with pins above and below the slots, it is Mini DVI. If it consists of a rectangular bar centered in a rectangular port, it is Micro DVI. Mini DisplayPort looks almost exactly like Micro DVI, only its bottom corners are rounded.

Step 2

If your second monitor has an input that corresponds to your computer's display output, purchase the appropriate cable for these ports. If not, you will also have to purchase an adapter. Mac sells adapters that can make its display outputs compatible with RCA, S-Cable or VGA monitor inputs. Consult the second link in Resources for a table of Mac adapters.

Step 3

Turn on your computer and your second monitor.

Step 4

Connect the adapter to your computer's display output port. On desktops, this is typically on the back panel. On laptops, it is on the side of the computer. Your computer's display may go blank momentarily. This is normal. Connect one end of the cable to the adapter and the other end to the second monitor.

Step 5

Click the Apple icon in the upper-left corner of your computer screen, and choose "System Preferences" from the drop-down menu.

Step 6

Click "Displays." Select "Arrangement" from the options near the top of the window. If the arrangement option isn't there, choose "Detect Displays" and wait while the computer searches for the new monitor.

Step 7

Locate a box labeled "Mirror Displays." If this box is checked, click to un-check it.

Step 8

Look for the two rectangles resembling computer screens in the center of the window. The one in the center represents your computer monitor, the other represents the second monitor. Click and drag the second monitor to the desired position. For example, placing it to the right of the other monitor extends the desktop to the right.

Step 9

Click and drag the menu bar from the center monitor to the one you just repositioned if you want the second monitor to be the primary monitor. If not, then skip this step.

Step 10

Click and hold any application window you wish to place on the second monitor. If you placed the second monitor to the right, then drag the window beyond the right edge of your monitor and it will appear on the second monitor.

Tips & Warnings

  • If your Mac fails to recognize the new monitor, try restarting your computer.