[BUG]

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?

When I launch the Claude desktop app, it eventually starts filling up my RAM by triggering a process or a watcher that fills up my non-page pool RAM.
I've tried several things and removed several functionalities, such as the Claude Chrome MCP, amongst other things. It has slowed down the fill-up of my non-page pool, however, it is still ongoing. It just fills up slower now. There doesn't seem to be any resolution in sight.

What Should Happen?

Not have all of my RAM occupied by random non-page pool fill up

Error Messages/Logs

From: C:\Users\[USERNAME]\AppData\Roaming\Claude\logs\main.log
(appears on every startup since at least 2026-05-24)

[Chrome Extension MCP] Watching Chrome for extension changes
[Chrome Extension MCP] Watching Edge for extension changes
[Chrome Extension MCP] Copied native host binary to ...\ChromeNativeHost\chrome-native-host.exe
[Chrome Extension MCP] Installed native host manifest for All at ...\ChromeNativeHost\com.anthropic.claude_browser_extension.json
[Chrome Extension MCP] Registering native host for Chrome in Windows registry: SOFTWARE\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_browser_extension
[Chrome Extension MCP] Registry verification successful for Chrome
[Chrome Extension MCP] Native host sync complete

Per-process I/O measurement (WMI Win32_Process delta over 5 seconds):
PID [Claude Desktop main window]
  Other ops/sec (file open/close/enumerate): 136,081
  Read ops/sec:                                    1
  Write ops/sec:                                   0

NtFC pool tag growth (NtQuerySystemInformation / SystemPoolTagInformation):
  Baseline (Claude not running):  ~150 MB
  30 min after launch:          3,849 MB
  40 min after launch:          5,746 MB
  Growth rate:                  ~130-200 MB/min

Attempting to remove Chrome Extension MCP components manually:
- Deleted chromeExtension key from claude_desktop_config.json
- Deleted HKCU\SOFTWARE\Google\Chrome\NativeMessagingHosts\com.anthropic.claude_browser_extension
- Deleted ChromeNativeHost manifest file
Result: All three were recreated automatically on the very next Claude Desktop launch.
Chrome/Edge were NOT running during any of these measurements.

Steps to Reproduce

To reproduce Root Cause 2 (Chrome Extension MCP watcher - affects all users):

1. Install Claude Desktop on Windows 11 with Chrome or Edge also installed
2. Launch Claude Desktop and log in
3. Open Task Manager > Performance tab > click "Open Resource Monitor"

In Resource Monitor > Memory tab, observe "Non-Paged" pool climbing continuously

1. Alternatively, run this in an elevated PowerShell to confirm the offending process:

$b=@{}; (gwmi Win32_Process -Filter "name='claude.exe'") | %{$b[$_.ProcessId]=$_.OtherOperationCount}
Start-Sleep 5
$a=@{}; (gwmi Win32_Process -Filter "name='claude.exe'") | %{$a[$_.ProcessId]=$_.OtherOperationCount}
$b.Keys | %{[pscustomobject]@{PID=$_;OpsPerSec=[math]::Round(($a[$_]-$b[$_])/5,0)}} | sort OpsPerSec -desc
Expected result: Claude Desktop main process showing 80,000-136,000 ops/sec

1. Check AppData\Roaming\Claude\logs\main.log for:

[Chrome Extension MCP] Watching Chrome for extension changes
[Chrome Extension MCP] Watching Edge for extension changes
These lines appear on every launch.

1. Reboot - the pool resets but resumes climbing within seconds of Claude Desktop restarting

To reproduce Root Cause 1 (session CWD watcher):

1. In Claude Desktop, open any session whose working directory is the user profile root

(check C:\Users\[USERNAME]\.claude\sessions\*.json for cwd: C:\Users\[USERNAME])

1. Observe the same 100,000+ ops/sec from the Claude Desktop process immediately
2. The app auto-resumes the last active session on launch, so this triggers on every startup

if any profile-rooted session exists in Recents

ANTHROPIC-BUG-REPORT.md

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.150 (Claude Code)

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_