3. Common Setup Problems

A few common problems getting UnityMCP Clients configured

macOS: Claude CLI fails to start (dyld ICU library not loaded)

• Symptoms

  • Unity MCP error: “Failed to start Claude CLI. dyld: Library not loaded: /usr/local/opt/icu4c/lib/libicui18n.71.dylib …”
  • Running claude in Terminal fails with missing libicui18n.xx.dylib.

• Cause

  • Homebrew Node (or the claude binary) was linked against an ICU version that’s no longer installed; dyld can’t find that dylib.

• Fix options (pick one)

  • Reinstall Homebrew Node (relinks to current ICU), then reinstall CLI:

    brew update
    brew reinstall node
    npm uninstall -g @anthropic-ai/claude-code
    npm install -g @anthropic-ai/claude-code

  • Use NVM Node (avoids Homebrew ICU churn):

    nvm install --lts
    nvm use --lts
    npm install -g @anthropic-ai/claude-code
    # Unity MCP → Claude Code → Choose Claude Location → ~/.nvm/versions/node/<ver>/bin/claude

  • Use the native installer (puts claude in a stable path):

    # macOS/Linux
    curl -fsSL https://claude.ai/install.sh | bash
    # Unity MCP → Claude Code → Choose Claude Location → /opt/homebrew/bin/claude or ~/.local/bin/claude

• After fixing

  • In Unity MCP (Claude Code), click “Choose Claude Location” and select the working claude binary, then Register again.

• More details

  • See: Troubleshooting Unity MCP and Claude Code

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FAQ (Claude Code)

• Q: Unity can’t find claude even though Terminal can.

  • A: macOS apps launched from Finder/Hub don’t inherit your shell PATH. In the Unity MCP window, click “Choose Claude Location” and select the absolute path (e.g., /opt/homebrew/bin/claude or ~/.nvm/versions/node/<ver>/bin/claude).

• Q: I installed via NVM; where is claude?

  • A: Typically ~/.nvm/versions/node/<ver>/bin/claude. Our UI also scans NVM versions and you can browse to it via “Choose Claude Location”.

• Q: The Register button says “Claude Not Found”.

  • A: Install the CLI or set the path. Click the orange “[HELP]” link in the Unity MCP window for step‑by‑step install instructions, then choose the binary location.

FAQ (VSCode)

• Q: When I first set up and start the Unity MCP server in VSCode, I get a failed response that says Canceled: Canceled [see image below]
  • A: Start a new chat, the bad chat didn't 'take' the MCP server configuration.