[BUG] Cowork MCP servers fail to connect on Mac Mini M4 — "Could not connect to MCP server" for mcp-registry and Claude in Chrome

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?

Cowork displays "Could not connect to MCP server mcp-registry" and "Could not connect to MCP server Claude in Chrome" on every launch. The MCP server connections are requested but never complete, despite all components being correctly configured and running.

What Should Happen?

Cowork should connect to both MCP servers (mcp-registry and Claude in Chrome) and display them as connected, enabling browser automation from Cowork.

Error Messages/Logs

On launching Cowork, two red error notifications appear:
1. "Could not connect to MCP server mcp-registry"
2. "Could not connect to MCP server Claude in Chrome"

The `main.log` shows repeated connection requests that never succeed:


2026-02-21 23:07:29 [info] [Claude in Chrome] MCP server registered
2026-02-21 23:07:30 [info] MCP Server connection requested for: mcp-registry
2026-02-21 23:07:30 [info] MCP Server connection requested for: Claude in Chrome
2026-02-21 23:07:33 [info] MCP Server connection requested for: mcp-registry
2026-02-21 23:07:33 [info] MCP Server connection requested for: Claude in Chrome


No "connected" status ever appears. The connection is requested, retried 3 seconds later, and then silently fails.

What's Working:

All individual components are functioning correctly:

- **Chrome native host** starts successfully, creates socket at `/tmp/claude-mcp-browser-bridge-<username>/2972.sock`, and enters its message loop (`chrome-native-host.log` confirms this)
- **Chrome extension** is installed, enabled, signed in, and extension ID matches `allowed_origins` in the native messaging host manifest
- **Native messaging host manifest** is correctly installed at `~/Library/Application Support/Google/Chrome/NativeMessagingHosts/com.anthropic.claude_browser_extension.json` with proper path and allowed origins
- **Cowork VM** boots successfully — `coworkd.log` shows the VM starting, mounting shared directories, connecting via RPC, and configuring network
- **Config file** (`claude_desktop_config.json`) is default/clean with no custom MCP servers

Steps to Reproduce

1. Install Claude Desktop (latest version) on Mac Mini M4 with macOS 26.3
2. Install Google Chrome with the Claude in Chrome extension
3. Sign into the Chrome extension
4. Open Chrome and open the Claude side panel
5. Launch Claude Desktop and navigate to Cowork
6. Observe the two "Could not connect" error notifications

Troubleshooting Already Attempted

• Fully quit and restarted Chrome and Claude Desktop (multiple times, in different orders)
• Opened Chrome side panel before launching Claude Desktop
• Checked for Claude Desktop updates (on latest version)
• Verified Chrome extension is enabled and signed in
• Verified native host manifest is correctly installed with matching extension ID
• Confirmed native host socket exists at /tmp/claude-mcp-browser-bridge-<username>/
• Confirmed Cowork VM boots successfully (coworkd.log shows clean startup)
• Uninstalled and reinstalled Claude Desktop (fresh download from claude.ai/download)
• Attempted to remove quarantine flags (sudo xattr -cr /Applications/Claude.app) — blocked by SIP

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Cowork 1.1.3963

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_