Question:

How can I use a USB-C adapter with dual HDMI ports to connect two external monitors to my Macbook Pro?

I have a Macbook Pro with two USB-C ports and I want to use two external monitors as extended displays. I purchased a USB-C adapter that has two HDMI ports, but when I connect it to my Macbook Pro, only one of the external monitors is detected. The other monitor turns on, but it shows the same content as the first one.

Is this a limitation of the USB-C adapter or the Macbook Pro? Do I need a different adapter or a different configuration to use two external monitors?

Answer:

If you have a Macbook Pro with two USB-C ports and you want to use two external monitors as extended displays, you might have encountered some issues with your USB-C adapter that has two HDMI ports. You might have noticed that only one of the external monitors is detected by your Macbook Pro, while the other monitor shows the same content as the first one. This can be frustrating, especially if you want to use the extra screen space for multitasking, gaming, or productivity.

In this article, we will explain why this problem occurs and how you can solve it using different methods. We will also provide some tips on how to choose the best USB-C adapter for your needs and how to configure your display settings on your Macbook Pro.

Why does my USB-C adapter only detect one external monitor?

The reason why your USB-C adapter only detects one external monitor is because of the way it handles the video signal from your Macbook Pro. There are two types of USB-C adapters that have dual HDMI ports: MST (Multi-Stream Transport) and SST (Single-Stream Transport).

MST adapters can split the video signal from your Macbook Pro into two independent streams, each with its own resolution and refresh rate. This allows you to use two external monitors as extended displays, meaning you can have different content on each screen. However, not all Macbook Pros support MST, especially the older models or the ones with Intel processors. If your Macbook Pro does not support MST, then your USB-C adapter will act as an SST adapter.

SST adapters can only duplicate the video signal from your Macbook Pro, meaning you can only use two external monitors as mirrored displays, showing the same content on both screens. This is why your second monitor is not detected by your Macbook Pro, because it is receiving the same signal as the first one.

How can I use two external monitors as extended displays with my Macbook Pro?

There are several ways you can use two external monitors as extended displays with your Macbook Pro, depending on the type of USB-C adapter you have and the type of Macbook Pro you have. Here are some of the most common methods:

• Use a USB-C adapter that supports MST and a Macbook Pro that supports MST. This is the simplest and most reliable method, as it allows you to use two external monitors as extended displays without any issues. You just need to connect your USB-C adapter to your Macbook Pro, and then connect your two external monitors to the HDMI ports on your adapter. Your Macbook Pro should automatically detect both monitors and allow you to configure them in the display settings. You can also use a USB-C dock that supports MST, which can also provide additional ports and features for your Macbook Pro.
• Use a USB-C adapter that supports MST and a Macbook Pro that does not support MST, but install a third-party software that enables MST. If your Macbook Pro does not support MST natively, you can try to use a third-party software that can enable MST on your Macbook Pro. One of the most popular software for this purpose is [DisplayLink], which can allow you to connect multiple external monitors to your Macbook Pro using USB-C adapters or docks that support MST. However, this method may not work for all Macbook Pros or USB-C adapters, and it may also affect the performance and quality of your displays. You should also check the compatibility and requirements of the software before installing it on your Macbook Pro.
• Use a USB-C adapter that supports SST and a Macbook Pro that supports Thunderbolt 3 or 4, and connect one external monitor to the USB-C adapter and the other external monitor to the other USB-C port on your Macbook Pro. If your USB-C adapter only supports SST, you can still use two external monitors as extended displays, but you will need to use both USB-C ports on your Macbook Pro. You will also need a Macbook Pro that supports Thunderbolt 3 or 4, which can deliver enough bandwidth and power for two external monitors. You can connect one external monitor to the HDMI port on your USB-C adapter, and then connect the other external monitor to the other USB-C port on your Macbook Pro using a USB-C to HDMI cable or adapter. Your Macbook Pro should detect both monitors and allow you to configure them in the display settings.
• Use a USB-C adapter that supports SST and a Macbook Pro that does not support Thunderbolt 3 or 4, and connect one external monitor to the USB-C adapter and the other external monitor to a USB-A port on your Macbook Pro using a USB-A to HDMI adapter. If your USB-C adapter only supports SST and your Macbook Pro does not support Thunderbolt 3 or 4, you can still use two external monitors as extended displays, but you will need to use a USB-A port on your Macbook Pro. You can connect one external monitor to the HDMI port on your USB-C adapter, and then connect the other external monitor to a USB-A port on your Macbook Pro using a USB-A to HDMI adapter. However, this method may not provide the best quality and performance for your displays, as USB-A ports have limited bandwidth and power. You may also need to install drivers or software for your USB-A to HDMI adapter to work properly.

How to choose the best USB-C adapter for your Macbook Pro and external monitors?

When choosing a USB-C adapter for your Macbook Pro and external monitors, you should consider the following factors:

• The type of USB-C adapter. As we mentioned earlier, there are two types of USB-C adapters that have dual HDMI ports: MST and SST. You should choose the type that matches the capabilities of your Macbook Pro and your display preferences. If you want to use two external monitors as extended displays, you should choose an MST adapter. If you only want to use two external monitors as mirrored displays, you can choose an SST adapter. You can also choose a USB-C dock that supports MST, which can offer more ports and features for your Macbook Pro.
• The resolution and refresh rate of your external monitors. You should also check the resolution and refresh rate of your external monitors, and make sure that your USB-C adapter can support them. Some USB-C adapters may have limitations on the maximum resolution and refresh rate they can output, especially if they are using SST. You should also check the HDMI version of your USB-C adapter and your external monitors, and make sure they are compatible. For example, HDMI 1.4 can support up to 4K at 30Hz, while HDMI 2.0 can support up to 4K at 60Hz.
• The power delivery of your USB-C adapter. You should also check the power delivery of your USB-C adapter, and make sure that it can provide enough power for your Macbook Pro and your external monitors. Some USB-C adapters may not support power delivery at all, or may only support a low wattage, which may not be enough to charge your Macbook Pro or power your external monitors. You should look for a USB-C adapter that supports at least 60W of power delivery, or more if you have a high-end Macbook Pro or external monitors. You should also check the power requirements of your external monitors, and make sure that they can be powered by your USB-C adapter or have their own power source.

How to configure your display settings on your Macbook Pro?

Once

you have connected your external monitors to your Macbook Pro using a USB-C adapter, you can configure your display settings on your Macbook Pro to suit your needs. Here are some of the steps you can follow:

– Open the System Preferences app on your Macbook Pro and click on Displays. This will open the display settings for your Macbook Pro and your external monitors. You can also access the display settings by clicking on the Apple logo on the top left corner of your screen, and then clicking on System Preferences > Displays.

– Arrange your displays. You can arrange your displays by clicking on the Arrangement tab in the display settings. You will see a blue rectangle representing your Macbook Pro screen, and one or two red rectangles representing your external monitors. You can drag and drop the rectangles to change their position and orientation. You can also check or uncheck the Mirror Displays option to choose whether you want to use your external monitors as mirrored or extended displays. You can also click on the white bar on the top of one of the rectangles to choose which display will be your primary display, meaning it will show the menu bar and the Dock.

– Adjust your resolution and brightness. You can adjust your resolution and brightness by clicking on the Display tab in the display settings. You can choose the resolution and brightness for each display by clicking on the corresponding rectangle. You can also choose between the Default for display option, which will automatically choose the best resolution for your display, or the Scaled option, which will allow you to choose from a list of available resolutions. You can also adjust the brightness of each display by using the slider or the buttons on your keyboard or your display.

– Adjust your color and rotation. You can adjust your color and rotation by clicking on the Color tab in the display settings. You can choose the color profile for each display by clicking on the corresponding rectangle. You can also calibrate your color by clicking on the Calibrate button and following the instructions. You can also rotate your display by clicking on the Rotation menu and choosing the desired angle. This can be useful if you want to use your display in portrait or landscape mode..