How to Fix MacBook Not Detecting External Display

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Matthew Wilhelm Kapell
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Most MacBooks come with a handy external display port to help you connect an external monitor. External monitors can be used to extend your desktop, create more visual space for more applications, or minimize distractions in public areas.

There's only one problem: MacBooks don't always detect when external displays are connected. If you try to connect one, all you might get is a blank, dead screen. The monitor may even turn on for a few seconds, only to go black moments later. It can be frustrating, especially if you have something urgent to take care of.



But do not worry. There are several troubleshooting methods that can help you fix the problem.

In this article, we'll go over every possible solution to help you get back on track.

How to Fix When a MacBook Doesn't Detect the External Display

Most MacBook owners like the idea of ​​an external monitor because of the many benefits it offers:

  • It can help you have a more immersive gaming experience by expanding your playing area.
  • If you're an artist or video editor, you can view your results on one monitor while using the other screen as your workspace.
  • Features such as multitasking and resizing screens can be done more efficiently on a large external monitor than on a small built-in screen.
  • If you plan to use multiple apps simultaneously, the increased screen real estate will help you stay organized. Your windows won't bang all over the place, which can save you valuable time.

But for all their benefits, external monitors don't always sync perfectly with MacBooks. Your Mac may even detect the monitor for a while and then lose connection after a restart.



If this has happened to you, there is no need to panic. The situation can arise for several reasons, and in this entry, we will go over some of the most common.

We'll also provide advice on how to resolve these issues so you can get back to work without delay.

Troubleshooting Method 1 – Check Your Cable Connection

Before trying anything complex, make sure both ends of the cord connecting the two devices are securely plugged in and plugged into compatible ports (such as HDMI or Mini DisplayPort). If the connection seems fine, but your MacBook still can't detect the external display, you can try changing the connection ports.

Troubleshooting Method 2 – Restart Your Computer

If your computer still fails to detect the external monitor even after verifying that all cables are securely and correctly connected, you should try restarting your Mac. A reboot is one of the oldest troubleshooting methods that can fix a myriad of connectivity issues, including external monitor detection issues.

When restarting your computer, you should not unplug the external monitor. Simply click on your Apple logo and select "Restart".

If restarting doesn't work, you can try putting your MacBook to sleep. To do this, click on the Apple logo and select “Sleep”. Then wait a minute or two before waking up your MacBook.

You can also activate sleep mode by simply shutting down your MacBook.

Troubleshooting Method 3 – Check Your Display Preferences

If you're having trouble connecting an external monitor to your MacBook, your display settings may not be configured correctly. To be specific, an external monitor may not work if your Mac's brightness and resolution settings are not correct.



Fortunately, it's easy to change your display preferences. Here's how:

  1. Click on your Apple logo and select "System Preferences".
  2. Click on “Show”.
  3. Click "Collect Screens" in the lower right corner of your screen. This will allow you to view the display settings of all monitors connected to your system.
  4. Try adjusting the brightness and color options of your external monitor. To cancel the changes, simply click on the “Esc” key.
  5. To adjust the image size on your monitor, click the Overscan or Underscan slider menus.

Besides your system's display settings, you may also consider checking your external monitor's display preferences. Some models require specific display settings to work.

Troubleshooting Method 4 – Connect a Test Monitor

Sometimes the problem can come down to a faulty monitor. If the external monitor you're trying to connect is faulty, tweaking the settings won't fix the problem. You will need to get a new monitor.


To find out if your monitor is faulty, disconnect it and then connect a second external display. If the second monitor works fine, the first monitor is either broken or incompatible with your MacBook.

Troubleshooting Method 5 – Update Your Operating System

Updating your computer's software and firmware can be a great way to fix many display issues that occur on MacBooks.

Here's how to perform a software update:

  1. Connect your computer to the Internet.
  2. Click on the "Apple" logo in the upper left corner of your screen.
  3. Select "Software Updates" from the menu that appears.
  4. Follow the on-screen prompts to download and install available software and firmware upgrades.

Turn your MacBook into a workhorse

With an external monitor, you can turn an already productive MacBook into a workhorse. In addition to creating space for more apps, you can avoid clutter or even lock yourself into a more immersive gaming experience.


That said, external display connection issues are relatively common. If your MacBook isn't detecting an external display, we've outlined several troubleshooting methods. Any of these can fix the problem and set you up with a more productive computing environment.

Have you had any problems connecting an external display to your MacBook? How did you get around them? Let us know in the comments section below.

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