How do I extend my display?

[gib88]

Hello,

I'm new to Macs. I'm much more familiar with PCs but I'm trying to migrate to Macs and I'm on a steep learning curve. One thing I'm trying to tackle is how to extend my monitor.

I've got 3 monitors: my main (embedded) monitor that comes with the Mac and 2 other separate monitors. When I plug them into my Mac, it duplicates the screen on all 3. I'd like it to extend the main one.

When I google how to do this, it tells me to open Display from System Preferences, click on Display Settings, and uncheck Mirror Displays. It also tells me to click on the Arrangement tab and arrange my monitors how I se fit:



But this is not what I see when I open Display or Display Settings. I see this:



There is no Mirror Displays checkbox and there is no Arrangement tab (or any tab).

What do I need to do in order to extend my display and arrange my monitors in the way I want?

Thank you.

 

[ferrarr]

First, which MBP do you have?

Model size and year?
Ports available use?
Or are you using a hub?

 

[MacInWin]

You have gone one click too far. When you first open System Preferences/Display, you should see something like this:


That shows from my MBP, the screen of the MBP on the left and my LG monitor on the right. The screens are aligned so the tops match because that is how I prefer it. To change the relationship, Click/hold on one and drag it to where you want it to "meet." Note that the mouse pointer only moves between the screens where they touch, so to move from the LG to the MBP in my setup, I need to have the mount in the top 3/4 of the screen when I move to the left or it gets stuck at the edge of the display.

So, in the first image you posted, drag/drop the one you want to move. I would suggest at a minimum dragging the monitor on the left down to maximize the overlap at the edges. Also, in the second image you posted the "Use As" defines what used to be mirroring. I have my MBP screen as the "Main Display" and my LG as "Extended display." The third option in the Use As: box is "Mirror for..." So, instead of turning off Mirroring, you just don't select "Mirror for.." and you are good to go.

 

[MacInWin]

Also, as an aside, I generally start at Apple.com for information about Apple products. Searching there instead of online at non-Apple leads to this: Change Displays preferences on Mac

And at that URL are more detailed instructions from the online Monterey User Guide.

 

[gib88]

ferrarr: First, which MBP do you have?

Model size and year?
Ports available use?
Or are you using a hub?

Here is a screen shot of the specs:



I'm using one port that splits into two for the two monitors.

MacInWin: That shows from my MBP, the screen of the MBP on the left and my LG monitor on the right. The screens are aligned so the tops match because that is how I prefer it. To change the relationship, Click/hold on one and drag it to where you want it to "meet." Note that the mouse pointer only moves between the screens where they touch, so to move from the LG to the MBP in my setup, I need to have the mount in the top 3/4 of the screen when I move to the left or it gets stuck at the edge of the display.

So, in the first image you posted, drag/drop the one you want to move. I would suggest at a minimum dragging the monitor on the left down to maximize the overlap at the edges. Also, in the second image you posted the "Use As" defines what used to be mirroring. I have my MBP screen as the "Main Display" and my LG as "Extended display." The third option in the Use As: box is "Mirror for..." So, instead of turning off Mirroring, you just don't select "Mirror for.." and you are good to go.

Thank you for this, MacInWin. This helped me convert my display settings to extended. However, it seems to only be recognizing one extended display:



The other extended display is mirroring the first extended display. I'm wondering if this is because they are connected to my machine through only one port and it doesn't recognize that the cable goes to two displays.

Thanks for the advice about going to apple.com first. I will remember to do that next time.

 

[Raz0rEdge]

The fact that you are seeing two displays being shown means that macOS has detected two monitors. If you are seeing your stuff mirrored on both displays, then click on Display Settings and choose Main display as the option for one of your monitors, on the other monitor, use the option Extended display as opposed to Mirror for <first monitor name> and the monitors will behave the way you want them to.

 

[IWT]

@gib88

I intrude here only to mention that the latest version of Monterey is 12.3

Your post shows 12.2. You might find, or not, that the latest update helps you??

Ian

 

[gib88]

The fact that you are seeing two displays being shown means that macOS has detected two monitors. If you are seeing your stuff mirrored on both displays, then click on Display Settings and choose Main display as the option for one of your monitors, on the other monitor, use the option Extended display as opposed to Mirror for <first monitor name> and the monitors will behave the way you want them to.

Well, that's not quite what I'm saying. It's more like this:



My machine detects 2 monitors (1 and 2) but there is a 3rd monitor that is not detected. Display 2 (which is not the main display) is mirrored on display 3. I suspect it's because the cable is running from my computer and splits on its way to monitors #2 and #3. My computer doesn't seem to recognize the split (I'm guessing) and thinks it's just one monitor.

IWT,

Thanks for the advice. I will try updating and see if that helps.

 

[MacInWin]

Are these three in addition to the internal monitor on the MBP? If so, your system won't support that many external monitors.

And just to be sure, EACH of the externals should be either MAIN (just one of them) or EXTENDED, none Mirrored. You do have to select each monitor to set it for the appropriate options. I don't have two externals, just one, so I can't screenshot what I mean.

EDIT : How are these monitors cabled? What port on the MBP, what type cable, what interface? You haven't said.

 

[Slydude]

I think we need to know exactly what hardware you are using to split that signal. Some splitters will not permit you to send a video signal to two external monitors simultaneouwsly. I have one like that. You can send a signal to port A or port B but not both simultaneously.

I do have another adapter/splitter that does not have that switch but it's still not able to send the computer's monitor signal to more than one external monitor at a time.

 

[krs]

How are these monitors cabled? What port on the MBP, what type cable, what interface? You haven't said.

That's exactly the questions I was going to ask.

My understanding was that the OP essentially has three screens - the one on the MBP and then screen 2 & 3 on two separate monitors.
And I thought the OP wanted to EXTEND the MBP screen (not mirror!) to each one of the two external monitors. So when the mouse cursor moves from left to right, it would first move across the MBP screen and then across screen 2 of the first external monitor left to right and then across screen 3 on the second external monitor.
I don't know if that is even possible to EXTEND the screen to two external monitors.

This also brings up the question of what is the model of the monitors and what input options do they offer?
I'm just fiddeling with my own very simple Mac/Monitor setup and learned just today that with Displayport/Thunderbolt one can daisy-chain up to 6 suitably equipped monitors.

 

[gib88]

Are these three in addition to the internal monitor on the MBP? If so, your system won't support that many external monitors.

And just to be sure, EACH of the externals should be either MAIN (just one of them) or EXTENDED, none Mirrored. You do have to select each monitor to set it for the appropriate options. I don't have two externals, just one, so I can't screenshot what I mean.

EDIT : How are these monitors cabled? What port on the MBP, what type cable, what interface? You haven't said.

There are 3 monitors all together, one embedded in the MBP, the other two external. There are 4 ports on the machine in total:



I have a bootcamp drive from which I an boot up in either Mac OS or Windows. When I boot in Windows, I'm able to extend my main screen to both external monitors, so I don't think the limitation is in the cable or the adaptor/hub itself.

 

[MacInWin]

Now I am totally confused. In the first post, the image you posted said the LG was "found" but there is no listing for the BENQ. Now you posted the BENQ is working but the LG is not recognized. So, I'm lost. You also didn't identify the dongle the two monitors are attached through. You said Windows recognizes both, which logically eliminates the dongle, the cables and the monitors, which leaves the settings in macOS. But if the BENQ isn't even listed in System Preferences, there isn't any way to make it un-Mirrored.

 

[gib88]

Now I am totally confused. In the first post, the image you posted said the LG was "found" but there is no listing for the BENQ. Now you posted the BENQ is working but the LG is not recognized. So, I'm lost. You also didn't identify the dongle the two monitors are attached through. You said Windows recognizes both, which logically eliminates the dongle, the cables and the monitors, which leaves the settings in macOS. But if the BENQ isn't even listed in System Preferences, there isn't any way to make it un-Mirrored.

The photo I posted that says the LC-50... is not recognized is probably a mistaken assumption on my part. My apologies for that. The screen shot in the OP is correct.

I'm not sure what you need to know. If you could ask for the information you need to know, that would help as I will do my best to get you that information. But unless you ask, I can only guess as to what information is important (though I will do my best to provide as much relevant information as I can think of).

In any case, if there is no way to "unmirror" monitors 2 and 3, that is fine. At least I know and won't waste my time trying to unmirror them. Thanks for pointing it out.

 

[MacInWin]

I didn't mean to say they cannot be unmirrored, just that until the second monitor is at least recognized and listed separately, it's not going to show the ability to do that unmirroring. Basically, the screenshot in the first post showing the MBP display and the LG display also needs to show the BENQ display so that you can set it to be an Extension, not a mirror. Something is keeping macOS from seeing the BENQ. I would suspect cable or dongle, but if Windows sees both, they would seem to be working. So, I'm stumped.

 

[ferrarr]

You may need to try an NVRAM or SMC reset. Here are the steps for the NVRAM reset;

Reset NVRAM on your Mac - Apple Support

If one or more settings stored in NVRAM don't work as expected on an Intel-based Mac, resetting NVRAM might help.

support.apple.com

 

[gib88]

I didn't mean to say they cannot be unmirrored, just that until the second monitor is at least recognized and listed separately, it's not going to show the ability to do that unmirroring. Basically, the screenshot in the first post showing the MBP display and the LG display also needs to show the BENQ display so that you can set it to be an Extension, not a mirror. Something is keeping macOS from seeing the BENQ. I would suspect cable or dongle, but if Windows sees both, they would seem to be working. So, I'm stumped.

I wonder if I need a different kind of adaptor/dongle. I'll visit my local electronics store and ask about this.

ferrarr: You may need to try an NVRAM or SMC reset. Here are the steps for the NVRAM reset;

Thanks ferrarr, I'll try this next time I reboot and report back.

 

[krs]

I'm trying to follow this thread (which is sometimes a bit confusing).

Going back to basics of the various video ports & protocols involved, I see:

2019 16" MacBook pro has a TB3 (USB-C) port
Sharp 50-inch external has composite and component video as well as DVI (no HDMI)
I assume DVI is used as the video input
BenQ has two HDMI 1.4 ports
@gib88 - all correct?

So does the "dongle" you are using (would be nice to know the model) have a USB-C port supporting TB3 as the input and then a DVI-D and an HDMI output?
Or is there another adapter between "dongle"and external screens?

The specs of the 1019 MacBookpro show this (there should be no limitation on the Mac side for a two external monitor setup):

2nd Display Support: Dual/Mirroring* 2nd Max. Resolution: 6016x3384 x2*


Details: *In addition to simultaneous support of the internal display, this model supports a maximum resolution up to 6016x3384 at 60 Hz at over a billion colors on up to two external displays or up to 4096x2304 resolution at 60 Hz at over a billion colors on up to four external displays via Thunderbolt 3 (USB-C)