Using an iMac as a display for other Macs

There is a feature on modern Macs known as Target Display Mode (TDM). Users who have an iMac and a Macbook Pro and may want to use their iMac as a large external display can follow these few short steps to use the iMac as an external display.

First make sure your iMac and Macbook Pro supports Target Display Mode by checking the chart below and make sure you have the support cable type.


Target Display Mode Compatibility List

iMac Model	Cable Supported	Port on Target Computer
iMac (27-inch Late 2009)	Mini DisplayPort to Mini DisplayPort	Mini DisplayPort or Thunderbolt
iMac (27-inch Mid 2010)	Mini DisplayPort to Mini DisplayPort	Mini DisplayPort or Thunderbolt
iMac (21.5-inch, Mid 2011)	Thunderbolt to Thunderbolt	Thunderbolt
iMac (27-inch, Mid 2011)	Thunderbolt to Thunderbolt	Thunderbolt
iMac (21.5-inch, Late 2012)	Thunderbolt to Thunderbolt	Thunderbolt
iMac (27-inch, Late 2012)	Thunderbolt to Thunderbolt	Thunderbolt

Plug your Macbook Pro into the iMac with a MiniDisplay cable to Thunderbolt cable and press ⌘-F2 on the display machines keyboard it will become a monitor for your laptop. 

Note: Both machines must be on and you must have both computer on 10.6.1 or higher. The machine running in TDM will continue to run all programs in the background and will stay awake as long as it is in Target Display Mode.

To get out of target display mode press the ⌘-F2 keys again on the machine keyboard acting as a display.

The camera, USB, Firewire, or other Thunderbolt devices are not available to the computer connecting in Target Display Mode. Just the display is accessed and used as an external monitor.