Apple products have a reputation for lasting longer than others. No matter what, eventually, you will have to upgrade to a newer machine. But what if your iMac is still working? We will explain how to repurpose your old iMac as an external monitor. All you need is an old iMac that supports Target Display Mode. Apple added the feature on iMac’s sold after 2009.
The caveat is that Apple retired the Target Display Mode with Retina Displays. However, there is a nifty workout just for this. We have listed the basic system requirements and multiple ways to use the old iMac as an external monitor.
System Requirements for Using Your iMac as a Secondary Display
If you are looking to use your iMac as a secondary display, you will need a few things to prepare your entire setup. What are those things?
The source Mac must be running macOS Catalina (10.15) or earlier.
- The 27-inch iMacs, which are Display mode-compatible, usually feature a Thunderbolt port or a bi-directional Mini Display port. So depending on which port is present in your iMac, you will need the Thunderbolt or the Mini DisplayPort cable to facilitate the connection between the two Macs.
- The macOS on the iMac should be High Sierra (10.13.6) or earlier.
- The source Mac must be running macOS Catalina (10.15) or earlier.
List of Compatible Macs
The iMac models released over the years 2011 and 2014 are all compatible with functioning as a secondary display.
- 2009-2010 27-inch Mac -that has a Mini DisplayPort
- 2011-2014 iMac – that has a Thunderbolt port.
Set up an Old iMac as an External Monitor Using Target Display Mode
The Target Display Mode feature (TDM) allows specific iMac models that have Thunderbolt or Mini DisplayPort interface to function as an external secondary monitor for another Mac. The latter Mac models do not have this feature because the power and port sustainability was becoming an issue with an increase in display quality.
Steps to Set up Target Display Mode
Let me show you how to enable Target Display Mode and use your iMac as a secondary display.
Time needed: 3 minutes
Follow the steps below to connect the two Macs and setup Target Display Mode.
- Turn on both the display iMac and the source Mac.
- Connect the two Macs with either Thunderbolt or a Mini DisplayPort cable.
- Usually, the connection happens automatically. If it doesn’t, then press Command + F2 to manually enter into TDM. You will then see the screen contents of your Mac being displayed on the iMac.
- When you are done with the system, you can press Command + F2 to manually exit Target Display Mode or you can just sever the cable connections between the two Macs to turn it off.
How To Control Brightness and Sound on the Display Mac?
There are two easy ways in which you can control the brightness and sound of your display Mac.
1. Move your mouse cursor on the screen of the display iMac and then press the keyboard buttons for adjusting brightness and sound.
2. Use the sliders on the menu bar item to control the sound and brightness of the second display Mac.
Fix Target Display Mode is Not working
If your Target Display Mode is not functioning properly, there is no need to panic. Here are some solutions which you can try out to fix the issue.
1. Instead of Command + F2, use Command + Fn + F2. This solution might help for some specific keyboard types.
2. Check and ensure that the Thunderbolt or the Mini DisplayPort cables are connected properly.
3. If you have already logged into the iMac that you intend to use as a secondary display, log out and come back to the login screen.
4. Booting up the display iMac from a Windows volume also might cause the issue. In that case, you will have to restart it from a normal Mac startup drive.
5. Some third-party keyboards create an issue while sending the Command + F2 prompt. In that case, it is advised to use a different keyboard or the keyboard that came with the Mac.
How To Use iMac as an External Monitor With Airplay?
The AirPlay feature allows you to receive audio, videos, and other content from nearby Apple devices (iPhone, iPad, or Mac). AirPlay is supported on Macs which run macOS 12 or later. If you wish to learn about the system requirements for the continuity of AirPlay across devices, you can go through Apple’s Support Guide.
Note: If your Mac is enrolled in an MDM (Mobile Device Management) system, the AirPlay Receiver may be unavailable on your device.
Set Up iMac To Become an AirPlay Receiver
Here is how you can set up your iMac as an AirPlay receiver.
1. Go to the Apple menu on your Mac.
2. Open System Settings and go to General in the sidebar.
3. Click on Airdrop & Handoff on the right side to turn it on.
You will find three options –
- Current user: Only the devices in which you are signed in with your own Apple ID can be used to stream content on this Mac.
- Anyone on the same network: Any nearby Apple device which has AirPlay enabled can stream content to this Mac.
- Everyone: Any nearby iPhone, iPad, or Mac can use this monitor to stream content.
4. If you wish to keep your iMac password protected, turn on Require Password and enter the password in the text field. Sometimes AirPlay might become sluggish. In such a scenario here’s how you can fix lagging AirPlay.
When Should You Use iMac as a Monitor?
If you need a second display monitor temporarily or on an urgent basis, using your iMac as a second display monitor is a great option. But if you are looking for a more permanent solution then I will advise getting a separate monitor for your requirements.
If you continue using an iMac as a secondary monitor for prolonged period, you will be wasting both power and the computing abilities of the iMac.
Old iMac Gets a New Lease of Life
Old iMac monitors are decent and good for a non-demanding workflow. The iMac will serve well as an external monitor instead of scrapping it as e-waste. Do note that we don’t recommend using newer iMacs as external monitors. Since it is better used as a standalone computer.