6 troubleshooting tips when your Mac's external display isn't working (2023)

Connecting an external display to your Mac makes it easy to work with multiple apps at the same time. Use the external monitor to extend your desktop, mirror your screen, or continue working on a larger monitor while your MacBook is closed.

If your external display isn't working with your Mac, these troubleshooting tips may help. In no time you'll be able to easily use your external monitor again for dual-screen multitasking.


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External monitor issues on your Mac

The following tips can fix a variety of issues you might be having with your Mac's external display. To make sure this is the best article for you, here is a short list of issues we'll show you how to fix:

  • Mac does not recognize external display
  • The external display appears white or black
  • The external monitor flickers and turns off
  • Lines or static cover the screen
  • Images appear blurry or out of focus
  • Images appear distorted or scrambled
  • Everything seems too big or too small
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This list is not exhaustive, but covers the most common external monitor problems. If your Mac's external display isn't working but you can't find the exact problem above, you can still fix it with the tips below.

Tip 1. Update all software on your Mac

Several software components are required for an external monitor to work with your Mac. There's your operating software (macOS), the specific app you're using, and the firmware built into your monitor, Mac, or even your cables.

If your external monitor isn't working at all, the first thing you should do is make sure everything is up to date.

open thisthrowmenu and go toSystem Settings > Software Updateto update macOS. Then open theAppstoreand clickUpdatein the sidebar to install application and firmware updates.

(Video) MacBook M1 Not Detecting External Monitor after macOS Monterey Update

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Finally, visit the manufacturer's website for your external monitor or video cable to see if other firmware updates need to be installed. You should also check for updates to any hubs, extenders, or adapters that you are using.

Tip 2. Check the compatibility of your external monitor

Unfortunately, not all external displays are compatible with all Macs. Even if you use an adapter to connect the two devices, they still need to be running compatible software for all features to work.

Visit the external monitor manufacturer's website for compatibility requirements. then go toApple > About This Macto ensure your Mac conforms to them. Click on thatsystem reportbutton for more information aboutthe ports of your Mac.

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It's important to realize that Thunderbolt 3 ports and USB-C ports are not the same, even though they look identical on the outside. If your monitor requires a Thunderbolt connection, you must connect it to a Thunderbolt port. The same goes for Thunderbolt 1 or 2 and MiniDisplayPorts on older Macs.

Tip 3. Reconnect all cables and use a different port

Disconnect the cables connecting your Mac to the external display. Before reconnecting, check connectors and cables for damage; You may needclean your doorwhen it's full of dirt.

If your external monitor still doesn't work after reconnecting it, try a different port on your Mac. Alternatively, you can connect to a different input on the screen if more than one input is available. You should also try connecting it with a different cable if you have spares lying around.

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Avoid using extension cords, hubs, or adapters. AttemptConnect your external monitor to your Macright on the spot. If this helps, then there is a problem with the accessory you are using.

(Video) MacBook Pro/Air Not Detecting External Monitor/Display - macOS Ventura/Monterey

Finally, make sure your Mac and external display are connected to power.

Tip 4. Restart your Mac with the external monitor connected

As always, it's a good idea to restart your Mac when something stops working, including your external display. Don't disconnect the screen before doing this, just open thethrowmenu and selectContinue.

If your external display still doesn't work after restarting your Mac, try putting it to sleep. open thisthrowmenu and clickSleep. Wait 30 seconds, then move your mouse or press a key to wake your Mac. If you have a MacBook, just close and reopen it to put it to sleep and wake it up.

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You also need to restart your external monitor. It's a good idea to unplug and plug it back into your Mac between power cycles.

Tip 5. Adjust your Mac's display system preferences

Your external monitor is probably not working properly because the settings are incorrect. It's easy to adjust these settings in System Preferences on your Mac. However, you must also change them on the monitor itself.

On the Mac, open thethrowmenu and go toSystem Settings > Displayto see your options. Click on thatjoin windowto see the system preferences for all your displays on your Mac display.

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Adjust your external monitor's brightness and color options. Then try the different resolution options. PressFleeto undo resolution changes when things get bad. You can also use theOverscanÖsub trapSlider to adjust the image size to fill the entire screen on your external monitor.

(Video) How To Detect Displays on Mac

See your external monitor's manual for information on adjusting the built-in options.

Tip 6. Detect screens connected to your Mac

Sometimes you can't use an external monitor on your Mac because your Mac won't recognize a new screen. Once you've ruled out software updates and physical connection issues, here are some more tips.

back toscreenspage in your system settings. Now hold down the buttonPossibilityon your Mac to arecognize screensbutton appears. Click here to have your Mac detect new connected displays.

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If that doesn't help, try starting your Mac in Safe Mode. To do this, press and holdExchangewhile your Mac boots up. Safe mode prevents third-party software and helper applications from loading at startup. It also performs a variety of maintenance tasks.

Booting into Safe Mode may be enough for your Mac to recognize external monitors. Reboot your Mac to exit Safe Mode, your external monitor should continue to work.

Use your iPad as an external Mac display with Sidecar

6 troubleshooting tips when your Mac's external display isn't working (8)

Hopefully your external monitor is now working with your Mac. If not, you should use your iPad. With the release of iPadOS and macOS Catalina, Apple added Sidecar so you can use your iPad as a second display for your Mac.

All you have to do is click on theair gamein your Mac's menu bar and select your iPad from the list of options. A macOS screen will appear on your iPad, extending your Mac desktop.

(Video) Fix Second Display not working in macOS Ventura

This feature is incredibly useful and easy to use. That means here it is.how to fix sidecar issuesif you come across one.

and lighter

Dan writes tutorials and troubleshooting guides to help people get the most out of their technology. Before becoming a writer, he studied audio engineering, oversaw repairs at an Apple store, and even taught English in China.

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