You can make a difference in the Apple Support Community!

When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

dual monitor adapter makes both external monitors mirror eachother

I have two monitors attached to my MacBook Pro 16". I bought a dual monitor adapter so I wouldn't need to use two adapters, but when I used it, both external monitors mirror each other instead of showing me 2 separate screens. When I use 2 separate adapters, one for each USB-C port, my monitors show me two separate screens like I originally wanted to have. Is there a way for me to use only one adapter or am I stuck with using two of them? I'll drop a picture of the dual adapter I was using.

MacBook Pro 16″, macOS 11.1

Posted on Jan 11, 2021 8:56 AM

Reply
Question marked as Top-ranking reply

Posted on Jan 11, 2021 12:35 PM

Look at: MacBook Pro 16-inch - Technical Specifications - Apple


According to that you can have up to 4 external displays attached. However, I note the specifications also mention it has 4 USB ports so I am interpreting this as meaning you have one independent display per port. I don't know but I am guessing each port can only supply video information for a single display. That's certainly the case with the M1 line. I am guessing your adapter is just duplicating the single feed it is receiving from that port.

Similar questions

3 replies
Question marked as Top-ranking reply

Jan 11, 2021 12:35 PM in response to kasiakonikowski

Look at: MacBook Pro 16-inch - Technical Specifications - Apple


According to that you can have up to 4 external displays attached. However, I note the specifications also mention it has 4 USB ports so I am interpreting this as meaning you have one independent display per port. I don't know but I am guessing each port can only supply video information for a single display. That's certainly the case with the M1 line. I am guessing your adapter is just duplicating the single feed it is receiving from that port.

Jan 11, 2021 9:01 AM in response to kasiakonikowski

Which exact model MBP?


Use multiple displays with your Mac - https://support.apple.com/HT202351

"Check how many displays your Mac supports: Choose Apple () menu > About This Mac > Support, then click Specifications. On the web page that appears, the number of displays your Mac supports appears under Video Support."


In particular if this is a M1 model: "If you're using a Mac with Apple silicon, you can connect a single external display to your Mac using one of the Thunderbolt / USB 4 ports. Docks don't increase the number of displays you can connect as an extended desktop."

Jan 11, 2021 9:39 AM in response to Limnos

I have a MacBook Pro MacBook Pro (16-inch, 2019).


I am able to use the two monitors but only when I have the screens connected to two separate ports. I am able to have two separate screens to work on while also using my MacBook monitor as well. the issue comes when I connect both monitors to 1 port with the adapter, the 2 connected screens mirror each other, so whatever I pull to one monitor, it shows on the other monitor as well, but it does not mirror with my Mac. so its acting like I have only 2 separate displays on, rather than 3. this only happens when I use the dual adapter which connects to one port only.

I tried looking at the specifications, like you mentioned, but it won't open the page...

dual monitor adapter makes both external monitors mirror eachother

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.