Why won't my MacBook Air, 2025 M4 detect Two Monitors despite using two usb c inputs into the Macbook?

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Why won't my MacBook Air, 2025 M4 detect Two Monitors despite using two usb c inputs into the Macbook?

I have already tested two methods to connect two monitors, but both have failed:

#1: Using my universal usb C docking station (with power supply) with display & hmdi cables going into it, and then into my mac through one usb C cable. It charges my mac and displays both monitors as mirrored - I have learned from reading other forums that this is because the dock is not thunderbolt, so is a dead end.

#2: I removed the display cable from the USB c hub and have connected it to a usb c converter cable, then directly connected that to my laptop in 1 of the 2 usb c ports. I then connect the usb c dock in the other port. When doing this, my laptop charges, but does not recognise the 2nd monitor that is being converted from displayport to usb c, directly into my laptop. Only the monitor that's going into the usb c dock is being recognised.

I'm about to test one final idea, but if this fails I'm not sure what else to do??

#3: (upcoming test) I will buy a hdmi to usb c converter, to then have both monitors being converted to usb c and being plugged straight into the laptop, and will charge the laptop with the lighting charger.

Is idea #3 definitely going to work? I'm so confused why idea #2 hasn't worked, considering online forums would suggest that solution should have worked.

My displays are:

VX2719-PC-MHD (via HDMI)

HP E24 G5 (via DisplayPort)

MacBook Air 15″

Posted on Feb 25, 2026 3:06 AM

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Answer 1

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Servant of Cats

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37,829 points

Feb 25, 2026 7:47 AM in response to user_321

user_321 wrote:

VX2719-PC-MHD (via HDMI)

ViewSonic – VX2719-PC-MHD 27” 240Hz Curved Gaming Monitor

This is a 27", 1920x1080 pixel monitor with a DisplayPort input and two HDMI v2.0 inputs. It has a refresh rate of 240 Hz.

Apple's Technical Specifications for your M4 MacBook Air don't promise support for any refresh rate over 60 Hz. However, https://support.apple.com/guide/macbook-air/use-an-external-display-apd8cdd74f57/mac (2025 – macOS Tahoe 26 version) claims that your Mac can support higher refresh rates. It says that a M4 MacBook Air can support

two external displays with up to 6K resolution at 60 Hz or 4K resolution at 144 Hz, or
one display with up to 4K resolution at 240 Hz or
one display with up to 8K resolution at 60 Hz.

In other words, while your Mac can drive a FHD display at 240 Hz, this comes at the expense of being able to use two external displays.

I don't know if reducing the refresh rate of that ViewSonic monitor to 144 Hz or less (if you can find a control for doing so in Displays Settings or in the monitor's own menus) will let the Mac recognize your other monitor, but it would certainly be worth a try.

HP E24 G5 (via DisplayPort)

HP – HP E24 G5 FHD Monitor (Technical Specifications)

This is a 23.8", 1920x1080 pixel monitor with a DisplayPort v1.2 input and a HDMI v1.4 input. HP doesn't specify the monitor's refresh rate, but I would assume that it can run at 60 Hz, and is probably not the cause of the problem.

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Answer 2

user_321 Author

Level 1

4 points

Feb 26, 2026 2:31 AM in response to user_321

PSA I solved the issue! It was the displayport cable I was using. I tested another cable and idea #2 is working now

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Answer 3

user_321 Author

Level 1

4 points

Feb 26, 2026 1:55 AM in response to user_321

To add to my post, I've also tried simply plugging in my HP monitor to the macbook via the usb c converter cable, but that alone is not recognised which is frustrating. The converter cable is 8K at 60Hz so it should not have any issues transmitting the data.

This makes me think my proposed idea #3 is pointless...? If the hp monitor won't connect on its own, why would it connect later on if I also have the viewsonic monitor plugged in via usb c to the macbook?

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Why won't my MacBook Air, 2025 M4 detect Two Monitors despite using two usb c inputs into the Macbook?

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