How to use an old iMac as an secondary monitor for MacBook

iMacs are excellent products that do not go out of fashion, or at least, always give you a new chance to use them. With new and increasingly demanding RAM memory software or requiring more powerful graphics cards, you can hardly use an old iMac as your primary location. In this article we see how to give a second life to an old iMac, turning it into a monitor for a new Apple Mac computer. In particular, we see how to use an old iMac as an external monitor of a MacBook.

If you have an old Mac, especially an iMac that you do not use because it is obsolete, that has a built-in monitor, maybe you’re wondering how to give it new life and then if you can use it as a second screen for the MacBook you just bought. Would not it be nice if you could connect it to the new portable MacBook and use it as a giant monitor? Maybe it will not have a retina display, but it is equally valid for many other things.

The good news is that it can be done. And now it is quite easy to use an iMac as a monitor for another Mac. In the past, to use it as a monitor you had to change the old Mac, or use some network software, but now Apple has met this need with an excellent feature called Target monitor mode. It means that this is an official solution provided by Apple.

Target monitor mode” to use an iMac as an external monitor

“Target monitor mode” is a feature introduced by Apple in the latest versions of the operating system. With Target Monitor Mode you can connect two Macs together and use one as a second display. Have you heard about Target Monitor Mode? Well, it’s the biggest cousin that lets you use a Mac’s hard drive like an external drive on an old Mac. Target monitor mode is a similar function, allowing you to use an old iMac as a monitor.

How to activate Target monitor mode

Target monitor mode is easy to use. All you need is an iMac that supports TDM and a Thunderbolt cable. Here’s how to set up TDM on your Mac:

  1. Connect two Mac computers using a Thunderbolt cable or a Mini DisplayPort cable.
  2. Make sure both computers are turned on and active.
  3. Press Command F2 on the keyboard of the iMac computer (the computer used as a display) to activate the Target Display Mode function. You will immediately see the other Mac’s desktop.

The new Mac screen should now appear on the iMac display. When you are finished, press the F2 Command on the Mac keyboard used as the display to exit the Destination Monitor Mode.

If “Use all keys F1, F2, etc.” has been selected in the Keyboard Preferences System as standard function keys, you need to use “Command-Fn-F2”. Apple suggests using an Apple keyboard (of the modern aluminum type) with special keys.

System requirements

Here are the iMac computers that support this feature to allow you to use an old iMac as a monitor:

  • iMac (27 inches end 2009)
  • iMac (27-inch Mid 2010)
  • iMac (Mid 2011)
  • iMac (Midi 2012 and earlier)
  • Note: The new iMac with 5K Retina Display from 2014 is no longer compatible with this function.

Target monitor mode requires that Macs have Mini DisplayPort or Thunderbolt connection. You must also have a specific model of iMac. On some of the older ones there is the Mini DisplayPort connection to Mini DisplayPort, or Mini DisplayPort to Thunderbolt and the new Macs use Thunderbolt connections to Thunderbolt. An iMac with OS X 10.6.1 or later is also required.

How to exit the destination monitor mode

If you no longer want to use your iMac as a monitor and exit the destination monitor mode, press the Command-F2 keys on the iMac keyboard. But even if you unplug the connection cable between the two computers or turn off the computer. If the Mac is turned off, the iMac screen will also turn off until the other computer is reactivated.

What you can control with the destination monitor mode

After connecting the Mac as a monitor, you can control various functions such as the brightness of the display, use the Monitor Panel, use System Preferences or adjust the brightness on the keyboard of the connected Mac.

You can also listen to the audio from the Mac connected by the integrated iMac speakers. Just select the latter from the Sound pane of System Preferences. You can adjust the volume and manage the playback of multimedia content via the audio keys on the keyboard of the connected Mac.

Attention, because the Mac you use as a monitor, you can not connect other devices to the ports or use the built-in camera. The accessories will be connected to the main Mac.

If something is not clear to you to use an old iMac as a monitor, Apple has a support page for target display mode that lists all Macs that support this feature with answers to other questions you may have.

Leave a Comment