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Why Isn’t My HDMI Working on My Mac?


We love our technological gadgets. We especially love connecting them for streaming purposes. 

That’s why the HDMI is such a valuable component for our iPhones and Macs. But sometimes, our HDMI cables don’t seem to work. So, why does HDMI not work with Macs?

Today we’re going to address several questions to help you find the answer you’re looking for. We’ll cover all the basics so you can troubleshoot your connections and start streaming again.

We’ll go in-depth on why your HDMI is not working on your Mac, why your Mac is not detecting your displays, and how to reset your HDMI port just in case.

For instance, a quick way to troubleshoot the problem is to disconnect your HDMI cable and plug it back in. If that doesn’t work, consider restarting the device you’ve connected to your Mac via HDMI cable. We’ll go in-depth in later sections of this article. 

In the following paragraphs, we will discuss other reasons your HDMI cable might not work on your Mac. So let’s start troubleshooting and get your HDMI/Mac connection up and running again.

Why Isn’t My HDMI Working on My Mac?

When connecting your Mac to an HDMI cable, sometimes it might not work correctly. However, several common factors can contribute to this issue.

For example, if you recently updated your Mac to OS Catalina, your HDMI cable might suddenly stop working. 

Perhaps it’s the USB C to HDMI adapter. Or, it could be that the HDMI port itself is not functioning properly. Although these scenarios are common, we’ll go over them and discuss possible solutions to these problems.

If your HDMI cable stopped working after you updated Catalina, several things may help.

Restart Your Computer

a Macbook with the logo macOS Catalina

A simple yet effective solution to many computer issues is to restart your Mac.

First, turn off your HDMI display while your Mac is still turned on.

Then disconnect your HDMI cable from your computer. 

Restart your Mac, now plug your HDMI cable back in, then turn on your HDMI display.

Although this solution is simple, it will fix many minor problems. However, if you’re still having issues, please continue reading for more solutions.

Ensure You Have Proper Privacy Settings

Privacy Settings

Sometimes the solution is a little more complex than you might imagine. However, ensuring you have the proper security and privacy settings for external displays may correct the issue.

To do this, click on the Apple symbol in the upper left corner of your screen. Choose the System Preferences menu option.

Now click on Security & Privacy > Privacy. Next, click Screen Recording from the menu. Click off Enable the Display Driver on the right.

Many displays are anti-piracy these days. Therefore, if this setting is turned on, it will give you a black screen to prevent anyone from duplicating the media on their devices.

Reset the SMC on Your Mac

After you’ve updated Catalina, resetting the System Management Controller (SMC) might help if you’re having issues using the HDMI cable.

To do this, you’ll have to follow a few steps.

  • First, turn your Mac off.
  • Once your Mac is off, hold the left Shift + Control + Option keys simultaneously. While you’re doing this, press your Mac’s Power button.
  • Next, wait 10 seconds.
  • Now turn your Mac back on.
  • This should reset your SMC.

However, if you’re using a Mac Mini, restarting your SMC is a little different.

  • First, shut down your Mac Mini.
  • Now, unplug your power cable from your Mac.
  • Wait 15 seconds or more.
  • Then plug the power cord back and turn your Mac Mini back on.

That’s it. It sounds more complicated than it is but this helps many people solve their HDMI issues.

If that didn’t help, perhaps the problem is something else. Continue reading for more answers to this common problem.

Turn Off HD Color

HDMI renders smooth and realistic color images on your screen. However, this might be giving you flickering issues when connected to your Mac.

Therefore turning off this feature is essential if you want the flickering to stop.

Although not all external displays have this feature, turning it off should solve the issue.

However, what if your Mac is not detecting your displays? How do you solve this issue? Let’s find out.

Why is My Mac Not Detecting Displays?

If you’ve connected your Mac to an HDMI cable and your Mac is not detecting your displays, it could be a few different things causing these issues.

The first thing you should check is your Display Preferences. It’s common to find out that these preferences are inaccurate. So here’s what you can do.

  • In the left corner of your screen, click on the Apple icon, then navigate to System Preferences.
  • Next, click on Displays.
  • Navigate to the area where it says Resolution and click on the Scaled button. 
  • Now, press and continue holding the Option key. This will reveal a hidden menu called Detect Displays at the bottom right.
  • Click the Detect Displays button. Doing this forces your Mac to detect external displays it might have missed.

resolution setting

If that doesn’t work, restart or sleep your Mac to force it as well.

So you’ve tried this method, and it didn’t work. Now what?

Are Your Resolution Settings Correct?

Let’s try something else. Let’s make sure the resolution for your external display is correct. Often, this is a simple fix that keeps people from detecting their displays correctly.

  • Let’s navigate to System Preferences by heading to the Apple symbol at the top left of your screen.
  • Head to the Displays section.
  • Look for the word Resolution. Click on the Scaled button to see a list of resolutions. 
  • Experiment with the resolutions here to see if it creates a change.
  • Underneath this, uncheck Automatically Adjust Brightness. Often the brightness is too low, and it looks like your computer is not detecting your display.
  • Raise the brightness to see if you can now see the image on your connected display.

Re-Check Cable Connections

Connect a HDMI cable to an USB-C to HDMI adapter for Macbook Air

Try re-checking cable connections if you tried the above troubleshooting techniques, and your Mac is still not detecting your HDMI display.

Checking your cable connections is easy. Check that your cable is securely connected to your Mac and your external display.

You can do this by disconnecting and then reconnecting them.

You can also troubleshoot by connecting the cable to another port. Or you can attempt to connect it to another external display to see if your Mac detects it.

Check Your Adapter

A common mistake among users is purchasing the incorrect adapter. Therefore it’s crucial to make sure you’re buying the correct one.

If you’re trying to connect your Mac to an external display via HDMI cable, your best bet is to get a Thunderbolt and USB-C  adapter.

Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter
Click image for more info

However, if your Mac already has an HDMI port, there’s no need for this adapter.

How do I Reset My HDMI Port on My Mac?

If your HDMI port is the issue and you want to reset it, here’s how you can do it.

  • For starters, we have to navigate to our System Preferences by clicking on the Apple icon at the top left of your Mac.
  • Once inside the System Preference menu, navigate to the Displays section.
  • Once you’re in the Display menu, click and hold the Option key to view a hidden button at the bottom right of the Display screen.
  • This button will read “Detect Display.” Clicking this button will force your HDMI port to detect any displays. In a sense, it’s resetting your port.

And There You Have It

Sometimes the reason your HDMI isn’t working on your Mac has a simple solution. Other times the answer is more complex. 

However, we hope we shed light on many of the common issues people encounter and their solutions.

At times, a simple restart will do. However, we understand that not everyone knows about the hidden menus within the Display screen.

When all else fails, checking your connections and playing with the resolution might solve the issue.

Nevertheless, we hope you learned why your HDMI connection is not working on your Mac, we also hope you learned how to fix it.

Last update on 2022-08-15 / Affiliate links / Images from Amazon Product Advertising API.


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