[BUG] Claude Desktop (macOS): main window stops responding after idle ("Main webview is unresponsive, will kill and reload"); Close/Open does not recover

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?

If Claude Desktop is launched and left idle, the main window eventually stops accepting any input (clicks, typing). Closing and reopening the main window does not recover it; only a full quit (Cmd+Q / force quit) and relaunch does.

main.log shows the app itself detecting the hang ("Main webview is unresponsive, will kill and reload") — 7 times since 2026-09-28. It happens both after system wake and with no system sleep at all (latest case: ~12h idle overnight, Mac awake the whole time).

Memory is NOT growing during idle: [process-memory] interval samples show tree_footprint_sum flat at ~1.03–1.10 GB overnight (main renderer ~460–485 MB). claude.ai-web.log is completely silent for the ~12h before the reload, i.e. the renderer appears fully stalled.

After every reload, claude.ai-web.log shows MaxListenersExceededWarning (EventEmitter leak) for several IPC channels and local MCP servers dropping mid-attach. This suggests the kill-and-reload path re-registers IPC listeners without cleaning up old ones, which may explain why Close/Open does not recover the window.

What Should Happen?

The main window stays responsive while idle, or the automatic webview kill-and-reload (and window Close/Open) fully restores a working UI without needing to quit the app.

Error Messages/Logs

# ~/Library/Logs/Claude/main.log
2026-09-28 08:52:05 [info] Main webview is unresponsive, will kill and reload
2026-09-30 16:47:34 [info] Main webview is unresponsive, will kill and reload
2026-10-03 08:53:01 [info] Main webview is unresponsive, will kill and reload   (~20s after system wake)
2026-10-03 11:50:47 [info] Main webview is unresponsive, will kill and reload
2026-10-03 21:39:58 [info] Main webview is unresponsive, will kill and reload
2026-10-03 21:47:59 [info] Main webview is unresponsive, will kill and reload
2026-10-05 09:31:10 [info] Main webview is unresponsive, will kill and reload   (~12h idle, no system sleep)

# claude.ai-web.log: no output at all from 2026-10-04 21:25:39 until the reload at 2026-10-05 09:31

# claude.ai-web.log right after each reload (229 MaxListenersExceededWarning in current log)
[warn] MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 ..._claude.web_$_LocalAgentModeSessions_$_sessionsBridgeStatus_$store$_update listeners added.
[warn] MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 ..._claude.settings_$_AppPreferences_$_preferencesChanged listeners added.
[warn] MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 ..._claude.web_$_WindowState_$_visibilityChanged listeners added.
[warn] [MCP] MCP server Control Chrome went away before the attach completed {"name":"SdkError","message":"Connection closed"}
[warn] [MCP] MCP server Control your Mac went away before the attach completed {"name":"SdkError","message":"Connection closed"}
[warn] [MCP] MCP server Desktop Commander went away before the attach completed {"name":"SdkError","message":"Connection closed"}

Steps to Reproduce

1. Launch Claude Desktop on macOS (local MCP servers enabled: Control Chrome, Control your Mac, Desktop Commander; Dispatch/remote sessions in use)
2. Leave the app idle (observed after minutes up to ~12 hours; occurs with and without system sleep)
3. Return to the app — the main window no longer responds to clicks or typing
4. Close and reopen the main window — still unresponsive
5. Only Cmd+Q / force quit and relaunch recovers

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude for Mac 2.19675.0 (5706e5), built 2026-10-01 (Desktop app)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Environment: Claude for Mac 2.19675.0 (5706e5), macOS 27.0.1 (26A434), Apple M1 Max.

This is the Claude Desktop app, not the CLI; Terminal/Shell field is not applicable.

Workaround: full quit (Cmd+Q or force quit) and relaunch.

Possibly related: #92005 (Windows: unresponsive after idle, stale lockfile on relaunch) and #23637 (window black after restore; React hydration error + EventEmitter leak on restore). This report is the macOS variant: no relaunch/lockfile problem here, but the app's own automatic webview kill-and-reload does not restore a working window.