Mac recognizing dual external displays as one monitor

The M1 MacBook Pro only supports one external monitor.

If you are using DisplayLink technology, you can attach more. DisplayLink requires not only a third-party software driver on the computer – but a DisplayLink implementation (chips and software) in the hub/dock or monitor that's going to implement the second video port or display. The driver creates a virtual software display, and then sends updates to that display to the matching hub or monitor over a data connection. So it's not as "first class" as direct monitor support in the M1's GPU, but it might work out for many productivity applications.

Looking at Dell's site, I see no indication that the WD22TB4 supports DisplayLink technology. I think it is counting on the fact that a Thunderbolt connection can carry two DisplayPort sessions. (Aside: This is something that the LG 5K and Apple 5K/6K displays rely on. They use both sessions, each carrying the signal for half of the display.)

Unfortunately, while the M1 chip is sophisticated enough to support a single 5K or 6K monitor, it does not appear to be sophisticated enough to support two independent monitors using either DisplayPort chaining or the two Thunderbolt / DisplayPort sessions. That's reflected in Apple's specifications, which say that the 13" M1 MBP supports a single external monitor, and that it has Thunderbolt 3. (Thunderbolt 4 certification would have required the machine to be able to drive two external displays.)

https://www.dell.com/en-us/shop/dell-thunderbolt-dock-wd22tb4/apd/210-bdqh/pc-accessories#techspecs_section

There may be other hubs that you can attach to your Mac that would support DisplayLink technology and would allow you to have a second monitor (using compressed video sent over USB-C). The Synaptics site lists some of them.

https://www.synaptics.com/products/displaylink-graphics

Just be aware that DisplayLink is not the same thing as DisplayPort. DisplayPort is a standard for the direct connection of a display to a device (computer, tablet, etc.), whereas DIsplayLink is a clever workaround for when your hardware doesn't support as many direct connections as you'd like.

I really wanted to use dual 8k monitors. I asked my Apple salesman in Manhattan Beach, CA "Does this MacBook support dual external 8k monitors?" He had me wait while he went ask someone in the back. He came out and said "Yes, of course it supports dual 8k monitors." and I spent almost $5000 thinking that was what I was getting.

I feel so used and stupid!

Shabiizz Said:

"Mac recognizing dual external displays as one monitor: [...]he problem is both monitors are on. and showing the same display as each other..[...]"

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Try Un-Mirroring the Screens to your Mac:

Hold Down: [command + F1] or [command + dim screen button]

Hello Shabiizz,

The reason you'd only be seeing one monitor in the display settings is because that computer model only supports one external monitor.

MacBook Pro (13-inch, M1, 2020) - Technical Specifications

Cheers!

More reading:

https://www.macrumors.com/2020/11/24/m1-macs-able-to-run-six-external-displays/

So u need to extend the display into dual monitors right ! You are using the wrong dock then,only "dell universal d6000" docking station can do that or the updated model of d6000 that is "UD 22" i font know more abt it. But currently i sm using universal d6000.

I just had this issue with an older MacBook Pro and a WD22TB4 Dell. I was surprised it wouldn't do two 32" 1080 monitors because I run a 39" curve on it with cad and video editing same time no issues.

on the back of the dell it has two display ports, one HDMI and one display port labeled USB C port. first issue was that I couldn't run the USB C [dp] and the hdmi at the same time, turns out the Dell manual says it MUX's these two ports together so you only get one or the other. I just happened to not have an extra [dp] to cdmi connector so thats why I was doing a bunch of weird stuff to get this working, so I got that working for my windows computer but then plug in the MacBook and it only does mirror two external monitors (or extend but both are mirrored). turns out, there is another USB C port on the back of the dell with the lightning bolt symbol, this is actual thunderbolt that passthrough to the Mac. So I used that and it works. idk if my MacBook is an M1 this was a 2015, I dont think it is, but this post came up so I wanted to answer for that search results also. Also I tested my MacBook by running two monitors through just the USB C to HDMI adapters and it works that way so I knew it should work but was blaming the Dell Hub. Cheers.

Re: “… [To] Apple salesman in Manhattan Beach, CA ‘Does this MacBook support dual external 8k monitors?’ … ‘Yes’ … “

That’s a truly unfortunate in-store experience as the specs for multiple external monitor support is clearly published for each device.

If he/she had only looked …