Mac OS High Sierra Not Detecting/Recognizing External Display (Monitor)? Here’s the fix


Normally your Mac will detect the external display when it connected to Mac. But many Mac users have a complaint that my Mac not recognizing external displays after updating to Mac OS High Sierra. Here I am going to tell you the solutions to fix this issue.
Before trying these solutions,

  1. Restart your Mac.
  2. Change your DisplayPort Adapter and try the new one. Because the problem may be in the DisplayPort Adapter.

Solution 1: Detect your Display

  1. Go to Apple Menu->System Preferences->Displays.
  2. Press and hold the Option key to show “Detect Displays” option.
  3. Click “Detect Displays” while holding the Option key.
  4. Now you can find the external display on your Mac.

Solution 2: Sleep and wake your display

  1. Go to Apple Menu->Sleep.
  2. Wait for few seconds and then wake the display by clicking mouse or pressing a key (any key) on the keyboard or clicking trackpad.

Solution 3: Enable Show mirroring options in the menu bar

  1. Go to Apple Menu->System Preferences->Displays.
  2. Enable (select) “Show mirroring options in the menu bar when available”.

Solution 4: Update DisplayLink driver
One of the Mac user said that updating DisplayLink Driver solved this issue. So update DisplayLink Driver on your Mac (or) uninstall and then reinstall DisplayLink Driver.

  1. Remove (uninstall) DisplayLink driver.
  2. Reboot your Mac.
  3. Install the latest DisplayLink driver and restart your Mac.

Click here to download the latest version of DisplayLink Driver.
Solution 5: SMC Reset
If your Mac has a non-removable battery,

  1. Shut down your Mac via Apple menu->Shut Down.
  2. Press and hold the Shift + Control + Option + Power Button simultaneously.
  3. Then release the keys at the same time.
  4. Press the Power Button to turn on your Mac.

If your Mac has a removable battery,

  1. Remove the battery from your Mac.
  2. Press and hold the Power Button for 5 seconds.
  3. Insert the battery into your Mac.
  4. Turn on your Mac.

Solution 6: Reset NVRAM/PRAM

  1. Turn off your Mac via Apple menu->Shut Down.
  2. Press the Power Button to turn on your Mac.
  3. Then immediately press and hold the Option + Command + P + R keys simultaneously as quickly as possible after pressing the Power Button. .
  4. Keep pressing until you hear the startup sound for the second time.

SEE ALSO: External Display Not Working on Mac
Solution 7: Restart your Mac in Safe Mode (Safe Boot)
Restart your Mac in safe Mode will fix many issues on your Mac. But you can’t use some features in Safe Mode.

  1. Turn off your Mac via Apple menu->Shut Down.
  2. Turn on your Mac.
  3. Press and hold the Shift Key as quickly as possible after you hear the startup sound. You can see the Apple Logo on the Screen.
  4. Keep pressing the Shift Key until you see the Login Window.
  5. Enter your User Name & Password to login. You may need to login twice if FileVault is turned on.
  6. Now check whether your mac can detect the external monitor or not.

Other Solutions:

  1. Check for Software Update.
  2. Restore your Mac to Factory Settings.
  3. Downgrade macOS High Sierra.

If you know any other solutions to fix this issue, let us know through your comments.

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