IS your mac supporting dual monitors? Some macs can only use one external display.
Check this first, for an intel mac, follow these instructions
- Choose Apple menu > About This Mac, double-click your serial number, then press Command-C to copy it.
- Go to the Tech Specs page, click the Search Tech Specs bar, press Command-V to enter your computer's serial number, then click Search.
- Click the specs page for your Mac. The number of displays your Mac supports appears under Video Support or Graphics.
For macs with apple silicon see
f you're using a Mac with M1 Max:
- On MacBook Pro, you can connect up to four external displays to your Mac using the Thunderbolt 4 (USB-C) and HDMI ports.
- On Mac Studio, you can connect up to five external displays to your Mac using the Thunderbolt 4 (USB-C) and HDMI ports on the back of the computer.
If you're using a Mac with M1 Pro:
- You can connect up to two external displays to your Mac using the Thunderbolt 4 (USB-C) and HDMI ports.
If you're using a Mac with the M1 or M2 chip:
- On MacBook Air, 13-inch MacBook Pro, iMac, and Mac mini, you can connect one external display using either of the Thunderbolt / USB 4 ports. On iMac, connect your display to either of the ports with the Thunderbolt symbol
. - On Mac mini, you can connect a second display to the HDMI port.
- Using docks or daisy-chaining devices doesn't increase the number of displays you can connect.
I have both an M1 iMac and an M1 MacBook Pro so I could only use one external display. But I connected an Apple TV to my second external display and I use that one now as an airplay display, so I can use 2 displays with my mac.