Using an external display with your Mac should be as easy as connecting the cable, but what if external display stopped working after updating to Big Sur? In this troubleshooting guide we’ll share all the fixes, tricks and techniques you can try to fix the external monitor not working on Big Sur issue.
How to fix external monitor not working on Big Sur issue
If external display stopped working after updating to Big Sur, then you can try the following fixes:
Fix #1. Disconnect and reconnect
Let’s begin with the easiest solution: power off your Mac and then power it back on! You can try a couple of different tricks:
- Unplug your adapter for about ten seconds.
- Plug the adapter back in.
If this doesn’t fix your issue, then:
- Unplug your adapter.
- Power off your Mac.
- Plug your adapter back in.
- Power on your Mac.
Some users have been able to resolve the issue by switching their monitor on and off while also detaching and reattaching the cable:
- Unplug the cable.
- Power down your monitor.
- Reattach the cable.
- Power up your external monitor.
Lastly, if you’re using a MacBook, you can try disconnecting while also closing your Mac:
- Build a connection between your Mac and the external monitor.
- Click on the “Apple” logo in your Mac’s menu bar.
- Click “Restart … ” and then immediately close your Mac’s lid.
If you find Big Sur not recognizing external monitor still, check the next solution.
Fix #2. Check your cables
Simply because a cable looks connected doesn’t mean that it is connected properly. Even a slightly loose connection can prevent your Mac from recognizing the attached display.
If you’re experiencing Big Sur external display issue, then consider detaching your cable and adapter and then re-attaching them firmly.
Fix #3. Don’t rely on battery power
If you’re running your MacBook from its internal battery, it may not have sufficient power to push pixels to an external monitor. Try plugging your MacBook to a power source to see whether this gives your computer sufficient power to run an external monitor.
Fix #4. Is your operating system up to date?
If your Mac is running an outdated version of operating system, then you may be encountering an issue that’s already been addressed in a recent update, so you should make sure that your device is running the very latest version of macOS.
Fix #5. Let your Mac take a power nap
Similar to the “turn it off and back on again” technique, you may be able to fix Big Sur not recognizing external monitor issue by letting your Mac take a quick power nap:
Step 1: Click the “Apple” icon in your Mac’s menu bar.
Step 2: Click “Sleep.”
Step 3: Wait a couple of minutes.
Step 4: Wake your Mac by interacting with its trackpad, mouse or keyboard.
Fix #6. Remove any chained adapters
You can’t force a Mac to work properly with an incompatible external display by chaining multiple adapters together!
If you have a chain of adapters, such as a Mini DisplayPort to DVI adapter chained to a DVI to HDMI adapter, consider replacing this setup with a single, compatible adapter.
Fix #7. Check the brightness, contrast and resolution
Your Mac’s brightness, contrast or resolution settings can hinder your display from appearing on an external monitor.
Follow the steps below to check that these display settings aren’t interfering with your external monitor:
- Click on the “Apple” logo in your Mac’s menu bar.
- Go to “System Preferences -> Display.”
- You can now look for any unusual or extreme settings or experiment by dragging the various sliders inside the “Display” menu.
Any extreme or strange color settings can prevent macOS from displaying on an external monitor.
You can also check that the brightness isn’t cranked down on your external display using the Ctrl + F2 keyboard shortcut.
Fix #8. Test with an alternative monitor
If your monitor is buggy, temperamental, or outright broken, then no amount of adjusting your Mac’s settings is going to fix the problem!
If you have access to a second external display, try attaching it to your Mac to see if it fixes Big Sur display issues. If your problem is fixed, then this strongly indicates that the problem lies with your external monitor.
Fix #9. Check your graphics card and drivers
If you’re using a third-party graphics card, check that the card is seated fully in the Peripheral Component Interconnect (PCI) slot and that you have the very latest version of all the necessary drivers.
New versions of macOS sometimes include driver updates, so you should also check that you’re running the latest version of macOS.
Fix #10. Use macOS’ hidden Detect Displays feature
If Big Sur doesn’t recognize your external display automatically, you can try to force the connection using macOS’s Detect Displays feature:
Step 1: Click the “Apple” logo in your Mac’s menu bar.
Step 2: Go to “System Preferences -> Displays.”
Step 3: Hold down the Option key, until you see a “Detect Displays” button on the screen.
Step 4: Select “Detect Displays” to see whether Big Sur recognizes the attached display.
Fix #11. Resetting NVRAM: Wipe your non-volatile RAM
Non-volatile random-access memory (NVRAM) is a small amount of memory where macOS stores all the settings it needs to access quickly, including some settings related to the display.
If these settings become corrupted, then it can cause a range of technical issues, so resetting your NVRAM may fix Big Sur external display issue.
Please note, resetting NVRAM will also reset your system settings and preferences, so you may need to reapply these settings following an NVRAM reset.
Please follow the steps below to reset NVRAM:
Step 1: Shut down your Mac normally.
Step 2: Turn on your Mac and immediately press the Option + Command + P + R keys.
Step 3: Hold these keys until macOS restarts, then release them.
You’ve now successfully reset your Mac’s NVRAM and can check if you are still experiencing Big Sur not recognizing external monitor issue.
Fix #12. Try resetting macOS’s SMC
The System Management Controller (SMC) is a chip that controls many of your Mac’s physical components, so resetting SMC can fix Big Sur external display issue.
Please follow the steps below to reset SMC:
Step 1: Make sure your Mac is completely switched off.
Step 2: Plug the power adapter.
Step 3: Hold down the Control + Shift + Option keys and the “Power” buttons for 10 seconds, then release all four keys simultaneously.
Step 4: Restart your Mac normally.
Fix #13. Using 4K? Make sure your Mac is compatible!
If you’re using a 4K external display, then there’s no guarantee that your graphics card will be powerful enough to push all of those pixels to the 4K display.
Typically, most Macs produced after 2013 are capable of supporting this resolution, but if you’re unsure, then check your Mac’s technical specifications for more information.
Fix #14. Strange colors? Switch to a different profile
Perhaps you’ve managed to get your external display up and running, but the colors are noticeably different to how they appear on your Mac’s built-in screen.
Some external displays feature contrast and RGB (Red, Green, and Blue) buttons that you can use to tweak the display’s color profile.
If your external display doesn’t feature these buttons, then you can often fix color-related issues using macOS’s Display Calibrator Assistant:
Step 1: Go to “System Preferences -> Displays.”
Step 2: Select the “Color” tab.
If you’re experiencing any issues with your Mac’s colors, then try switching to a different color profile.
Step 3: Select “Calibrate … ” This will launch macOS’s Display Calibrator Assistant.
You can tweak your Mac’s colors, using the Display Calibrator Assistant.
Step 4: Follow the onscreen prompts to calibrate your display.
Alternatively, you can try out various color profiles to see whether any of these profiles are a better fit for your external display. To select a new profile, go to “System Preferences -> Displays – > Color,” then explore the various color profiles on the list.
We hope the above tips have helped you resolve your external display not working on Big Sur issue. If you have any other questions, let us know in the comment section below.
Agê Barros says
Thanks. The step #13 solved my problem (and saved my day). I am running a MacBook Pro 15 inch 2018 with a Dell and a old iMac 27″ mid 2010 as second screen.