Claude Code 2.1.143 hangs during subprocess initialization with UNC additionalDirectory

Title: Claude Code 2.1.143 hangs during subprocess initialization when user settings include a UNC additionalDirectory

Environment:

• OS: Windows
• Claude Code CLI: 2.1.143
• CLI path: C:\Users\<user>\.local\bin\claude.exe
• Also observed with VS Code Claude Code extension 2.1.143
• Shell: PowerShell

User-facing error:

Error: Subprocess initialization did not complete within 60000ms -- check authentication and network connectivity

Summary:

Claude Code can hang during startup when ~/.claude/settings.json contains a UNC path in permissions.additionalDirectories. The resulting error points users toward auth/network connectivity, but auth and HTTPS connectivity were healthy. The issue was isolated to one user-settings entry.

Confirmed behavior:

• claude --version returns immediately.
• claude auth status reports logged in.
• TCP and HTTPS connectivity to api.anthropic.com and claude.ai succeeds.
• claude --setting-sources project,local -p ping succeeds.
• claude --setting-sources user -p ping times out when the UNC additional directory is present.
• Removing only the UNC additional directory makes both of these succeed:

claude --setting-sources user -p ping
claude -p ping

Minimal repro shape:

{
  "permissions": {
    "allow": [],
    "additionalDirectories": [
      "\\\\server.example.local\\NETLOGON\\tools"
    ]
  },
  "effortLevel": "high",
  "theme": "auto",
  "autoUpdatesChannel": "latest"
}

Observed result:

claude --setting-sources user -p ping
# hangs until external timeout

Expected result:

Claude Code should either:

• start successfully with the UNC path,
• ignore or defer validation of unavailable/slow UNC paths,
• or fail fast with a clear settings validation error naming permissions.additionalDirectories.

Additional notes:

• Testing each additionalDirectories entry individually found that normal local paths and one root-like Windows path (\tmp) succeeded.
• The UNC path alone reproduced the timeout.
• A debug run stopped after user settings were loaded and before the command completed. The raw debug log is not included because it contains historical command text from local permission rules.
• Earlier investigation also found that PowerShell summaries can make missing/null JSON values look like count 1; raw JSON inspection is safer when diagnosing extraKnownMarketplaces.

Workaround:

Remove UNC paths from ~/.claude/settings.json under permissions.additionalDirectories, then restart the VS Code extension or Claude Code process.