[BUG] Claude Desktop (MSIX) silently exits ~20s after launch on Windows 10, Surface Book 2 — regression after update from 1.2581.0 to 1.3109.0

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?

Title: Claude Desktop (MSIX) silently exits ~20s after launch on Windows 10, Surface Book 2 — regression after update from 1.2581.0 to 1.3109.0
Summary
Claude Desktop launches, signs me in, and silently disappears approximately 20 seconds later with no user interaction. No error dialog, no window freeze, no Windows notification. The app worked reliably on version 1.2581.0 and broke immediately after updating to a newer version around 15 April 2026. Currently on 1.3109.0 (the version released 16 April 2026 to fix a separate startup crash), but the issue persists.
Environment

Claude Desktop version: 1.3109.0.0 (MSIX / Microsoft Store install)
Package: Claude_1.3109.0.0_x64__pzs8sxrjxfjjc
OS: Windows 10
Hardware: Microsoft Surface Book 2
GPUs: Intel integrated + NVIDIA discrete (NVIDIA drivers are old/unsupported)
System locale: en-ZA
Antivirus: Windows Defender only (no third-party)
Last known working version: 1.2581.0.0
First broken version: whichever update was pushed on or around 15 April 2026

Reproduction steps

Launch Claude Desktop from Start menu
App opens with me already signed in
Do not touch the app, do not click anything
Window disappears silently approximately 20 seconds later

100% reproducible across multiple launches, including after a full Reset (Settings → Apps → Advanced options → Reset) and after uninstall + reinstall.
Troubleshooting already performed (all failed to resolve)

Kill all Claude processes, reinstall fresh from claude.com/download — no change
Verified on fixed version 1.3109.0 (not the known 1.3036.0 startup bug) — no change
Full MSIX Reset via Settings → Apps → Advanced options → Reset — no change
Removed orphaned Squirrel install folder at %LOCALAPPDATA%\Claude — no change
Disabled NVIDIA discrete GPU in Device Manager — no change
Confirmed no MCP servers or desktop extensions configured (claude_desktop_config.json contains only enterpriseConfig: {} and _cfprefsMigrated: true)

Diagnostic findings
No crash entry in Windows Application event log. No Windows Error Report generated. No Claude-written log file produced in the MSIX LocalCache folder during the crash window. Only evidence of the app running is in C:\ProgramData\Claude\Logs\cowork-service.log, which shows the Claude client connecting to CoworkVMService, entering the RPC loop, then the connection ending with "failed to read length: EOF" — consistent with the client process disappearing, not the service terminating it.
This signature (silent exit, no crash dump, no app log, no Windows error) suggests the Claude main process is exiting cleanly from Windows' perspective rather than hitting an unhandled exception — something is calling process exit rather than crashing.
Relevant CoworkVMService log excerpt:
2026/04/17 10:46:25.341160 Starting CoworkVMService as Windows service
2026/04/17 10:46:25.536734 [Server] Service: C:\Program Files\WindowsApps\Claude_1.3109.0.0_x64__pzs8sxrjxfjjc\app\resources\cowork-svc.exe
2026/04/17 10:46:25.537242 Service ready. Listening on \\.\pipe\cowork-vm-service
2026/04/17 10:46:49.676334 [Server] Client connected
2026/04/17 10:46:51.787480 [Server] Client signature verified (subject: Anthropic, PBC)
2026/04/17 10:46:51.787480 [Server] Persistent RPC: entering loop
2026/04/17 10:47:34.445808 [Server] Persistent RPC: connection ended: failed to read length: EOF
Pattern repeats identically across many launches over multiple days.
Impact
Desktop app completely unusable. Falling back to claude.ai in browser. Lose access to desktop-specific features (Cowork, desktop extensions, local MCP servers).

What Should Happen?

Claude desktop app should open and stay open, not crash.

Error Messages/Logs

N/A - none.

Steps to Reproduce

N/A - ?system specific

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

1.2581.0

Claude Code Version

1.3109.0

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_