[BUG] Claude Desktop blank screen on macOS - GPU compositing fails to paint on Apple Silicon (M1 Pro)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Desktop shows a completely blank/empty window on startup. The web content loads (verified via logs showing navigation to claude.ai/login) but the GPU compositor fails to paint it to the screen.

Key finding: The content IS loaded in memory - performing a macOS window swap (Mission Control swipe) and returning to Claude causes the content to appear. This confirms it's a GPU compositing/painting issue, not a content loading issue.

Root Cause Analysis

The issue manifests as a GPU compositing failure where the Electron renderer loads content but fails to paint it. Diagnostics:

1. --disable-gpu flag fully fixes the issue - launching with /Applications/Claude.app/Contents/MacOS/Claude --disable-gpu --disable-gpu-compositing renders correctly every time
2. Normal launch shows blank screen but window swap/repaint forces content to appear
3. React error #418 appears in logs as a secondary symptom (hydration mismatch likely caused by the blank paint state)
4. Full cache/data nuke did NOT fix it - only disabling GPU did
5. Network connectivity confirmed working (curl to claude.ai succeeds)

Relevant Log Errors

# GPU-related blank screen with React hydration failure
Uncaught Error: Minified React error #418; visit https://react.dev/errors/418?args[]=HTML&args[]=

# EventEmitter leak from repeated retry attempts
MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 listeners added.

# Content actually loads (navigation works)
topFrameUrl: 'https://claude.ai/login?returnTo=%2Ftask%2Fnew'
[info] claude.ai account details provided

Environment

• App Version: 1.1.3189 (1b7b58)
• Platform: macOS 15.3 (Darwin 25.3.0)
• Architecture: arm64 (Apple Silicon)
• CPU: Apple M1 Pro
• RAM: 32 GB
• Electron: 40.4.0

Steps to Reproduce

1. Launch Claude Desktop normally on macOS with Apple Silicon (M1 Pro)
2. Observe blank/empty window - no UI rendered
3. Use Mission Control or window swap gesture - content appears on return
4. Quit and relaunch with --disable-gpu - renders immediately every time

What Should Happen?

Claude Desktop should render its web content immediately on launch without requiring a window repaint trigger.

Workarounds

1. Best: Launch with --disable-gpu --disable-gpu-compositing flag
2. Quick: After launch, switch away from the window (Mission Control) and switch back to force repaint

Related Issues

• #10995 - React Hydration Error (the #418 error is a secondary symptom of this GPU paint failure)
• #11093 - Duplicate of #10995
• #21803 - White/blank screen after Windows Hibernate (similar symptom, different platform)
• #21764 - Code tab shows black screen