How to Fix a Black Screen Issue on macOS

If your pen display shows a black screen when connected to a Mac, please check the following steps:

• Verify Your Cable and Port Connections
  1. Ensure the HDMI cable is securely connected to your Mac computer, whether you're using a 3-in-1 cable, 3-in-2 cable, or a single HDMI cable.
  2. If you are using a USB‑C to USB‑C cable, make sure it is a full‑featured USB‑C cable that supports video output. Many USB‑C cables only support power and data, not display.
  3. Connect the cable to a Thunderbolt or USB‑C port that supports display output. Not all USB‑C ports on a Mac support external displays.

If your cable and port setup is correct and the screen is still black, the issue may be related to a known macOS bug affecting external displays. Please try the steps below. If the first option doesn't resolve the issue, proceed to the second.

• Option 1: Reset WindowServer Preferences (Finder Method):
  1. Open Finder.
  2. Click Go in the top menu bar.
  3. Hold down the Option key — this will reveal the Library folder. Click Library.
  4. Delete the following files (if present):
     • /Library/Preferences/com.apple.windowserver.plist
     • /Library/Preferences/com.apple.windowserver.displays.plist
  5. Open the folder:
     • /Library/Preferences/ByHost/  
       Delete all files named:
     • com.apple.windowserver.*.plist
  6. Restart your Mac.
     Your display settings will reset to default.
• Option 2: Reset WindowServer Preferences (Terminal Method)
  1. Open Terminal:
     1. Launchpad → type Terminal → open
     2. Or go to Applications > Utilities > Terminal
  2. Enter the following commands one at a time, pressing Enter after each:
     • rm ~/Library/Preferences/ByHost/com.apple.windowserver.*.plist
     • sudo rm /Library/Preferences/com.apple.windowserver.plist
  3. If the second command fails, try:

     • sudo rm /Library/Preferences/com.apple.windowserver.displays.plist

  4. Restart your Mac.

If You're Not Comfortable With These Steps

If you're unfamiliar with accessing the Library folder or using Terminal, we recommend contacting Apple Support for assistance. They can help you safely perform these steps or provide alternative solutions.