The owner of a MacBook Pro has reported that their macOS is unable to detect an external display. Many MacBook Pro owners use their notebooks for content creation, and an external monitor simplifies the editing process by providing the ability to add or adjust tracks, images, and elements in the editor. In this guide, I will show you how to fix an issue where your MacBook Pro is unable to detect an external monitor.
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Why is the MacBook Pro not detecting the external monitor?
It seems like there might be a minor issue with the external monitor or the macOS machine. I have explained a few valid reasons why the Mac could be having problems detecting an external display. Although we cannot rule out a hardware problem, we suggest a solution later on. I will not be going over the most common solutions found in other guides. Instead, I recommend trying some advanced guides that could be helpful in resolving the issue.
Hidden Resolution:
macOS software misses out on the external monitor resolutions sometimes. The computer detected the display, but it’s not available to use due to the hidden screen resolutions. You have to unlock the screen resolution and enable the secondary monitor in the system.
Undetected EDID:
The Pro model couldn’t detect the display because the software couldn’t read the Extended Display Identification Data (EDID). Windows is good at reading EDID, and that’s why you have fewer display connectivity problems on it. We have to take a roundabout method to resolve the external display detection issue. But it’s worth your time, and M1 Silicon users may face challenges.
SIP:
Have you heard of SIP (System Integrity Protection)? macOS software prevents unauthorized code from accessing the computer. It’s an advanced protection layer to prohibit third-party codes from registering in the system. I have shown you how to access the SIP settings in the MacBook.
Adapters:
Are you using an adapter? Hub?
Apple should have bundled a supported hub or adapters for the owners. The manufacturer charges premium prices on the notebooks and doesn’t provide adapters in the box. The adapter or hub connects the external display. There is a solution available for adapter users, and I have mentioned it below.
Recognized as TV:
The external monitor may have been recognized as a television unit and not an additional display. There is a way to fix the issue and let macOS know about the secondary display.
Boot Camp (Windows):
Many Intel and AMD MacBook Pro users are running Windows via Boot Camp. The Boot Camp (Windows) couldn’t detect the external display. Many users have shared screen resolution and scaling complications in the Boot Camp. I have shared a solution below, and you can resolve it by following the tutorial.
Cables:
The cables might be faulty, and grab a spare HDMI cable from the desk. Test the spare HDMI cable and connect the secondary display with the Pro model. Visit Walmart or any online store to purchase a high-quality HDMI cable from a brand.
FIX: MacBook Pro is not Detecting External Display
We will use third-party apps from the App Store select screen resolution. We will avoid using any third-party program to prevent any security loopholes.
Restart MacBook Pro
Many Pro models don’t see a good night’s sleep for weeks. You have to let the notebook sleep for half an hour a day.
a. Remove all cables, such as charging cable, HDMI cable, Hub (dock), removable devices, etc.
b. Remove the external monitor power cable and HDMI cable.
Follow my lead to turn off the Pro model.
1. Click on the Apple menu icon.
2. Click on the “Shut down” button.
3. Let the MacBook sleep for half an hour.
Let MacBook sleep for five minutes if you don’t have half an hour.
4. Reconnect the cables and turn on the macOS machine.
A good night’s sleep gives the hardware to discharge the electricity. The software loads drivers, services, and background apps again. Most software-based problems will resolve after rebooting the system.
Power Sequence Issue (USB-C-DP Dongle)
Many external display users utilize USB-C to DP dongles to create connections. The Mac computer must have puzzled over the device type, and the adapter could be the reason for the secondary display detection failure. You can apply a temporary solution for the time being.
1. Connect HDMI cable to Mac computer.
2. Remove the power cable from the monitor.
3. Wait for a few seconds, and I recommend a minimum of 30 seconds.
4. Connect the power cable and turn on the monitor.
5. Your Mac should detect the new monitor in a second.
Most Pro computers should detect the 1080p and 2k monitors by forcing the detection system.
Wrong DisplayPort Cable
Mac computer released after 2019 has the latest Thunderbolt technology. Apple stuck with Thunderbolt ports in the latest computers, and they are not planning to add HDMI or DP ports in the future. Millions are using after market adapters and cables or dock to connect external monitors. You are using the wrong DP cable and creating an unnecessary challenge for the Pro model.
A. You might be using USB-C to Thunderbolt 2 dongle.
B. Buy USB-C to Mini DisplayPort dongle.
Yes, the latest Thunderbolt 2 and Mini DisplayPort have the same port. The adapter supports 40K@60Hz and purchases the product from a reputed brand.
Missing Screen Resolution
The manufacturer designed the Pro model to handle 4k resolution displays. Many external monitors have problems with macOS software because it hides the extra screen resolutions. Of course, you can access the additional screen resolutions from the settings, or an app from the App Store does the job for you. Let’s look at the official method and set the native screen resolution.
1. Click on the Apple menu logo.
2. Choose “System Preferences” from the drop-down menu.
3. Choose “Displays” from the settings.
4. Press the “Option” key while while left-clicking.
5. The additional screen resolutions shows up on the screen.
Now, set the native screen resolution of the external monitor. Meanwhile, you can download and install EasyRes by Chris Miles or SwitchResX for plug & play experience.
Disable SIP (System Integrity Protection)
I have mentioned the SIP in the reasons lists, and you can refer to it for more information. Some risks come after disabling the SIP in the macOS machine. The software no longer protects the system from third-party code registration. I recommend that users pay attention while installing a third-party program. The installation packages and tools should come from a verified publisher.
1. Shut down your Mac computer.
2. Let the Mac computer shut down.
3. Press and hold the power button until the Recovery mode appears on the screen.
4. A message appears on the screen “Continue holding for startup options.”
5. Keep holding the power button, and another message appears “Loading startup options.”
6. Release the power button when “Macintosh HD” and “Options” appear on the screen.
7. Click “Options” from the startup selection and press continue.
8. Choose the administrator user and click on “Next” to move forward.
9. Enter the lock screen password and click on the “Continue” button.
10. Click on “Utilities” from the top menu.
11. Choose “Terminal” from the drop-down menu.
12. Copy and paste the (csrutil disable) command.
13. Press the Return key (Mac keyboard) or Enter key (Windows keyboards).
14. Enter the “Y” key and press the Return key (Mac keyboard) or Enter key (Windows keyboards).
15. Enter the username of the computer.
16. Enter the lock screen password.
Give the Terminal a few seconds to apply the new settings.
17. Mission success when the Terminal has a “Restart the machine for the changes to take the effect” message.
Restart the Mac, then connect the external display and use it as a secondary monitor.
Override EDID Data
Overriding the EDID data is an advanced task, but it will fix the external display detection problem. Follow the tutorial and bear with me. Carry a Windows machine or run Windows in Boot Camp. Microsoft developed “Microsoft Basic” drivers for the monitors. We will create a supported EDID data file and override it in the macOS system.
a. I will be using the Lenovo Windows 11 machine.
b. Grab a minimum 2GB flash drive to carry the files.
Most M1 Mac can’t run Windows since Microsoft didn’t create a license for the Boot Camp. I used an actual Windows PC instead of (Boot Camp) Windows.
1. Download, extract and launch the Monitor Info View program on your Windows PC.
2. Select the monitor and click on “View” from the top menu.
3. Choose “Lower Pane” then select “EDID Hex Dump” to continue.
4. The Hex information appears at the middle portion. You have to copy the hex information marked in red color, and I have shared a snapshot.
5. Go to edidreader website and paste the hex information manually.
6. I have pasted the hex information by copying one row after another. Click the “Parse Edid” button.
7. Your monitor EDID data generated.
Note: Disable SIP, and I have shared the information above.
8. Download and Install the PlistEdit Pro app.
9. Locate (System/Library/Displays/Overrides) and copy a random folder with one file inside.
10. Paste the copied folder in the desktop.
11. Open “Terminal” from the utility folder.
12. Copy and paste the ( ioreg -lw0 > ~/Desktop/ioregSaved.txt) command in the Terminal.
13. Press the “Return” key.
14. A new (ioregSaved.txt) created in the desktop.
15. Open the text file.
Now, you have to search for each item and paste the EDID data in the text file.
16. Search “IODisplayEDID” in the EDID data generated from the website.
Result: “IODisplayEDID” = <0x00 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0x00 0x09 0xD1 0xE7 0x78 0x01 0x01 0x01 0x01 0x21 0x1E>
You have to copy the hex file from Monitor Info View program.
17. Search for “DisplayVendorID” from the generated hex file.
Result: “DisplayVendorID” = 19619
Copy the value in the text file because it’s not present in the generated EDID data.
18. Search for “DisplayProductID” in the text file.
Result: “DisplayProductID” = 13140
Copy the value in the text file because it’s not present in the generated EDID data.
19. Search for “IODisplayPrefsKey” in the text file.
Result: “IODisplayPrefsKey” =
"IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/IGPU@2/AppleIntelFramebuffer@1/display0/AppleBacklightDisplay-4ca3-3354"
Note down the last colored values.
Time to edit the custom file.
20. Choose “DisplayVendorID-4ca3“.
Rename the folder from “IODisplayPrefsKey” =
IOService:/AppleACPIPlatformExpert/PCI0@0/AppleACPIPCI/IGPU@2/AppleIntelFramebuffer@1/display0/AppleBacklightDisplay-4ca3-3354.
21. Choose “DisplayProductID-3354“.
22. Open what you renamed earlier using PlistEdit Pro.
23. Copy and paste the XML command.
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>DisplayProductID</key> <integer>13140</integer> <key>DisplayProductName</key> <string>Internal LCD</string> <key>DisplayVendorID</key> <integer>19619</integer> <key>IODisplayEDID</key> <data> AP///////wBMo1QzAAAAAAASAQOAJhV4CoWVmVdPjyYhUFQAAAABAQEBAQEBAQEBAQEB AQEBHCpATGGEHjAwICUAftcQAAAZAAAADwAAAAAAAAAAAC76BngAAAAA/gBTQU1TVU5H CiAgICAgAAAA/gAxNzNLVDAxLUswMQogAEs= </data> </dict> </plist>
Rename the DisplayProductID, DisplayProductName, Internal LCD (you can name anything), DisplayVendorID, and IODisplayEDID. All information is available above.
24. Don’t save the file in any extension format like PHP.
25. Paste the custom EDID folder in the (System/Library/Displays/Overrides) location.
26. Fix the permissions and reboot with Disk Utility.
The MacBook Pro will detect the external display after providing the EDID data manually. You can raise your concerns on any Apple forum if you need customized assistance from the community.
Bottom Line
Go through the basic troubleshooting to fix MacBook Pro not detecting the external display. I skipped basic troubleshooting in this guide since every guide covers the standard solution only. You can hunt for advanced solutions in forums regarding custom EDID data creation. Let us know which solution helped you in connecting the external display successfully.