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[Solved] External Display Flickering at High Refresh Rates on MacBook Pro 16″ M3 Pro: How to resolve DSC compression and VRR handshake failure over USB-C DisplayPort

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Home › Forums › MacBook, iMac & macOS Lab › [Solved] External Display Flickering at High Refresh Rates on MacBook Pro 16″ M3 Pro: How to resolve DSC compression and VRR handshake failure over USB-C DisplayPort

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  • November 15, 2026 at 12:56 am #16048
    Chloe Clark
    Community Contributor
    Diagnostic Hardware Specs: MacBook Pro 16″ M3 Pro | OS Version: macOS Sequoia 15.0.1 | Archive Source: Apple Support Community #256434809

    I am running into a persistent issue on my MacBook Pro 16″ M3 Pro running macOS Sequoia 15.0.1.
    Whenever the machine encounters DSC compression and VRR handshake failure over USB-C DisplayPort, the following diagnostic log appears in Console:

    WindowServer: [com.apple.WindowServer:server] Display 0xaa38 link training failure / DSC buffer renegotiation

    I verified that hardware connections are intact and tested across different power sources. What is the verified diagnostic procedure to permanently eliminate this symptom?

    MacBook Air 13″ M3 (16GB) | Apple GSX Terminal | Thermal Camera Seek Compact | Belfast, UK
    Apple Certified Service Technician (ACiT / ACSP) | "Verified Apple Discussions Archive"
    November 15, 2026 at 12:56 am #16049
    Kelly Reyes
    Community Contributor
    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.

    iMac 24″ M3 (16GB) | AST 2 Diagnostic Station | ESD Workstation | Vancouver, BC
    Apple Certified Support Professional (ACSP) | Apple Certified Service Technician (ACiT / ACSP)
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