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Reply To: [Solved] External Display Flickering at High Refresh Rates on macOS Sequoia 15.0.1: Diagnostic steps and permanent fix

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Home › Forums › MacBook, iMac & macOS Lab › [Solved] External Display Flickering at High Refresh Rates on macOS Sequoia 15.0.1: Diagnostic steps and permanent fix › Reply To: [Solved] External Display Flickering at High Refresh Rates on macOS Sequoia 15.0.1: Diagnostic steps and permanent fix

November 14, 2026 at 6:20 pm #9896
Sarah Mitchell
Apple Master (Lvl 10)
Apple Recommended / Verified Community Solution
This canonical solution was verified and marked as solved in the Apple Support Community archive.

Locking refresh rate to a fixed frequency, disabling Variable Refresh Rate (VRR), and regenerating WindowServer display plists.

Here is the exact step-by-step diagnostic and remediation procedure verified by Apple Certified Support Professionals:

  1. In System Settings > Displays, set Refresh Rate to fixed 120Hz or 100Hz instead of Variable (VRR).
  2. Reset display preferences: 
    sudo rm -f /Library/Preferences/com.apple.windowserver.displays.plist
rm -f ~/Library/Preferences/ByHost/com.apple.windowserver.displays.*.plist
killall -9 WindowServer
  3. In monitor physical OSD menu, set DisplayPort mode to ‘DP 1.4 Standard’ without aggressive DSC overdrive.

Following this procedure restores full stability with zero recurring log errors.

Apple Certified Support Professional (ACSP)
Cupertino, CA | "Precision Apple Diagnostics"