Fix Claude Code Installation on macOS: Homebrew, Node.js 26, and Gatekeeper

The Problem

You try to run claude on macOS and hit one (or all) of these:

1. Binary conflict — /opt/homebrew/bin/claude already exists from an old npm global install
2. Node.js v26 crash — the CLI launches via Node.js v26.0.0 and immediately crashes
3. Gatekeeper block — “Apple could not verify claude is free of malware”

This guide walks through the complete fix I used to get Claude Code v2.1.149 running cleanly.

Root Cause

The install is half-conflicting: Homebrew tries to install the new claude-code cask, but /opt/homebrew/bin/claude already exists from a previous npm install -g @anthropic-ai/claude-code. The existing binary runs through Node.js v26.0.0, which is too new and causes compatibility crashes.

Step 1: Identify the Conflict

# See what currently owns the claude binary
which claude
ls -l /opt/homebrew/bin/claude

If it points to a Node.js script or npm global, that’s your problem.

Step 2: Remove the Old npm Install

# Remove the global npm package
npm uninstall -g @anthropic-ai/claude-code

# Remove the stale binary if still there
rm -f /opt/homebrew/bin/claude

Step 3: Reinstall via Homebrew Cask

# Clean install of the official cask
brew install --cask claude-code

# Verify
claude --version

Expected output:

2.1.149 (Claude Code)

Step 4: Fix Node.js Version (If Still Crashing)

If Claude still launches via Node and crashes, switch from v26 to LTS:

brew uninstall node
brew install node@22
brew link --overwrite --force node@22

# Verify
node -v   # Should show v22.x.x
claude    # Should work now

Step 5: Fix macOS Gatekeeper Block

When you see “Apple could not verify claude is free of malware”:

Option A — System Settings UI:

1. Run claude (it will fail)
2. Go to System Settings → Privacy & Security → Security
3. Click “Open Anyway” (appears for about 1 hour after the blocked attempt)
4. Run claude again

Option B — Terminal (if you trust the Homebrew source):

xattr -dr com.apple.quarantine /opt/homebrew/bin/claude
xattr -dr com.apple.quarantine /opt/homebrew/Caskroom/claude-code
claude

Step 6: Nuclear Option (Clean Reinstall)

If nothing else works:

brew uninstall --cask claude-code
rm -f /opt/homebrew/bin/claude
brew install --cask claude-code
claude

First-Time Setup

Once Claude Code launches, you’ll see the welcome screen with a theme selector:

1. Auto (match terminal)
2. Dark mode ✔
3. Light mode
4. Dark mode (colorblind-friendly)
5. Light mode (colorblind-friendly)
6. Dark mode (ANSI colors only)
7. Light mode (ANSI colors only)

Use arrow keys to select, press Enter. You can change this later with /theme.

Summary

Related Content

• Claude Code Bootcamp Workshop — May 30, 2026
• Karpathy’s CLAUDE.md: Encoding LLM Discipline
• Garry Tan’s gstack: 23 AI Specialist Tools