If you own an older iMac with a stunning 27-inch 5K display sitting on your desk gathering dust, it feels incredibly wasteful to buy a brand new, expensive external monitor for your MacBook. Apple recognized this years ago and created a brilliant feature called Target Display Mode.
Target Display Mode allows you to physically connect a MacBook to a compatible iMac using a single cable, completely bypassing the iMac’s internal computer and utilizing its massive, high-quality screen purely as an external monitor for your laptop.
Hardware Limitations and Compatibility
Before you purchase cables, you must understand that Apple officially deprecated and killed this feature years ago. Target Display Mode does not work on modern Macs, Apple Silicon (M1/M2/M3) Macs, or modern versions of macOS.
To use Target Display Mode, your hardware must meet highly specific, strict requirements:
- The iMac (The Monitor): The iMac being used as the screen must be a 24-inch or 27-inch model manufactured between 2009 and 2014. It must also be running macOS High Sierra or earlier. (A 2015 iMac or a 2021 iMac cannot be used as a monitor).
- The MacBook (The Source): The laptop sending the video signal must have been manufactured in 2019 or earlier, and it must be running macOS Catalina or earlier.
If your hardware is even one year too new, the software will actively block the connection.
How to Connect the Computers
If you have verified that both your vintage iMac and your older MacBook meet the strict hardware requirements, the setup process is remarkably simple.
- Ensure both the iMac and the MacBook are powered on and logged in to a user account.
- Connect the two computers using the appropriate cable. (Depending on the exact year of your iMac, you will need either a standard Mini DisplayPort cable or a Thunderbolt 1/2 cable).
- Once the cable is securely plugged into both machines, sit in front of the iMac.
- Press the Command (⌘) key and the F2 key on the iMac’s keyboard at the exact same time.
The screen on the iMac will flash black for a brief second. When the screen turns back on, the iMac’s native desktop will be gone, replaced entirely by your MacBook’s desktop environment.
How to Exit Target Display Mode
While the iMac is acting as a monitor, its internal computer continues running quietly in the background. If you need to access a file saved on the iMac’s hard drive, you can instantly switch back.
Simply press Command (⌘) + F2 on the iMac’s keyboard again. The video feed will disconnect, your MacBook will shrink back to its own internal display, and the iMac will resume showing its own native operating system exactly where you left off.