MacBook Black Screen After macOS Sequoia or Sonoma Update: How to Fix

The Software Update Blackout Bug

A common cause of sudden display failure occurs during major macOS upgrades (such as updating to macOS 15 Sequoia or macOS 14 Sonoma).

The update flashes the T-CON display firmware alongside the Apple Silicon bootloader (iBoot). If third-party display extensions (like DisplayLink, Duet Display, or Flux) are active during the reboot, the WindowServer compositor crashes into an infinite loop, leaving the screen completely black with an active cursor or blank backlit canvas.

3-Step Recovery Workflow

1. Boot into Safe Mode:
   • Turn off Mac completely.
   • Press and hold Power button until "Loading startup options" appears.
   • Select your drive, hold Shift, and click Continue in Safe Mode.
2. Clear WindowServer Preferences: Delete /Library/Preferences/com.apple.windowserver.displays.plist.
3. Deploy DisplayGuard to prevent driver sleep drops.