[BUG] Claude in Chrome — Native Messaging Host IPC Failure on Windows

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?

Environment

• OS: Windows 11, LAPTOP-3G03G7QE
• Claude Desktop: latest (reinstalled 6/3/2026)
• Chrome extension: Claude in Chrome (Beta) v1.0.74, extension ID fcoeoabgfenejglbffodgkkbkcdhcgfn
• Plan: Claude Max
• Organization ID: 4088a71c-fc28-49f2-b909-bd68fed50358

Summary
The Claude in Chrome connector shows a connected browser (list_connected_browsers returns Browser 1) and select_browser succeeds, but tabs_context_mcp and tabs_create_mcp always return "No tab available". Browser automation is completely non-functional despite all configuration being correct.

Root Cause Identified
The native messaging host (chrome-native-host.exe) launches successfully but the IPC channel back to Claude Desktop fails silently.

Diagnostic Findings

1. Registry key missing after initial install: HKCU\Software\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_browser_extension was not created by the installer. Required running Claude Desktop as Administrator to force registry creation.

1. After registry creation, all files confirmed correct:

• Registry key: HKCU\Software\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_browser_extension → C:\Users\ASUS\AppData\Roaming\Claude\ChromeNativeHost\com.anthropic.claude_browser_extension.json
• JSON file: exists, correct format, correct extension ID in allowed_origins
• chrome-native-host.exe: exists (989 KB), .NET Framework 4.0 application

1. Windows Event Viewer (Application log):

• Event ID 1022, .NET Runtime, 10:38 AM: chrome-native-host.exe (PID 19420) launched successfully. Benign profiling warning (HRESULT 0x80004005), NOT a crash.
• No Event ID 1000 (Application Crash) for chrome-native-host.exe — confirmed not crashing.

1. browser connection confirmed: list_connected_browsers returns deviceId fc26b5e0-c3a0-4337-82aa-f99e32c9a271 (Browser 1, Windows, local). select_browser succeeds without error.

1. Tab creation fails: Both tabs_context_mcp (createIfEmpty:true) and tabs_create_mcp return "No tab available" immediately after select_browser.

1. No antivirus interference: Only Windows Defender (default) is present.

Conclusion
The native messaging host starts and the browser connection exists, but the IPC channel between chrome-native-host.exe and Claude Desktop does not establish. This is a Windows-specific IPC implementation issue — the host process runs but cannot communicate back to the Desktop app.

Additional context

• This setup worked correctly in previous sessions (May 22–30 and June 2 morning) with tabIds 1644813053, 1644813326, 1644815706
• Issue began when starting a new conversation thread on June 2 afternoon
• Pop-up blocker was blocking claude.ai (now fixed: added to Chrome allow list)
• Running Desktop as Administrator during initial setup was required to create the missing registry key
• Chrome extension side panel (Sonnet 4.6) successfully connects and controls the browser — only the Desktop app connector fails

What Should Happen?

Claude Desktop should be able to create and control browser tabs via the Claude in Chrome connector. After selecting the connected browser with select_browser, tabs_context_mcp and tabs_create_mcp should return a valid tab ID, allowing browser automation from the Desktop app.

Error Messages/Logs

tabs_context_mcp (createIfEmpty:true): "No tab available"
tabs_create_mcp: "No tab available"
switch_browser: "No tab available"

Windows Event Viewer - Event ID 1022, .NET Runtime, 10:38 AM:
".NET Runtime version 4.0.30319.0 - There was a failure initializing profiling API 
attach infrastructure. HRESULT: 0x80004005. Process ID: 19420."
(Note: this is a benign warning, NOT a crash - no Event ID 1000 for chrome-native-host.exe)

Steps to Reproduce

1. Install Claude Desktop on Windows 11
2. Install Claude in Chrome extension v1.0.74
3. Enable Claude in Chrome connector in Desktop Settings → Connectors
4. Open Chrome and navigate to any website
5. In Claude Desktop conversation, call list_connected_browsers → returns Browser 1 successfully
6. Call select_browser with the deviceId → succeeds without error
7. Call tabs_context_mcp with createIfEmpty:true → returns "No tab available"
8. Call tabs_create_mcp with a URL → returns "No tab available"

Note: Registry key HKCU\Software\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_browser_extension
was NOT created by the installer — required running Desktop as Administrator to force creation.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

June 2, 2026 morning session (tabIds: 1644813053, 1644815706)

Claude Code Version

N/A - Claude Desktop app (not Claude Code CLI)

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

<img width="778" height="529" alt="Image" src="https://github.com/user-attachments/assets/754891f5-d61e-4af1-881c-656b3bd7eed7" />

This issue affects Claude Desktop app (Claude in Chrome connector),
not Claude Code CLI. The bug report template is being used as the
closest available option for Desktop app issues.