[BUG] Claude Desktop crashes immediately after Cloudflare Turnstile screen on Windows 11 25H2 — reproducible across clean installs

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?

Claude Desktop reaches the Cloudflare/Turnstile challenge screen on launch, then crashes immediately every time. This is fully reproducible — it has happened across 7+ clean reinstalls in a single session, with no successful launch.

Environment

• Claude Desktop version: 1.24012.9 (MSIX)
• Windows edition: Windows 11 Pro, version 10.0.26200 (25H2)
• Install method: MSIX via official installer (Claude Setup.exe from claude.ai/download)
• Package: Claude_pzs8sxrjxfjjc

Troubleshooting Already Attempted (no change to outcome)

• Full uninstall and clean reinstall (repeated 7+ times)
• Windows Firewall disabled entirely
• DNS unaffected (default network config, no proxy/VPN in use)
• Enabled Windows Containers, Windows Hypervisor Platform, and Virtual Machine Platform features (this did fix a separate, earlier-stage issue — see "Related finding" below — but did not fix the crash itself)
• Confirmed no third-party antivirus or system proxy is configured

Related Finding: Windows Containers issue (now resolved on this machine)

Initially, cowork-svc.exe logs showed Failed to load vmcompute.dll: The specified module could not be found, caused by the Windows Containers/Hypervisor Platform/Virtual Machine Platform features not being enabled by default on a 25H2 clean install (same root cause as #28231). Enabling those three Windows features and rebooting resolved that specific error — HCS now initializes correctly (vmcompute.dll loaded successfully, HCS ready). This is a separate issue from the Cloudflare crash below and may be worth documenting/automating in the installer for other 25H2 users, but it is not the cause of the crash this report is about.

Installer Log (ClaudeSetup.log) — installer itself is healthy

Every install attempt completes successfully with no errors:

MSIX package installed successfully
No Squirrel installation found, skipping uninstall
MSIX installation succeeded
Launching Claude...
=== Claude Setup completed successfully ===
Elevated process exited with code 0

This ruled out the installer/bootstrapper as the source of the problem — the progress bar disappearing is just the installer window closing normally after success, not a crash.

Main Process Log (main.log) — crash signature

Immediately after launch, every network request the app makes returns 403, and the Turnstile challenge never completes:

Navigation to https://claude.ai/ failed with status code 403
Health check returned non-200 status: { status: 403, statusText: '' }
[account] IPC did not provide accountUuid, falling back to bootstrap API
[account] Bootstrap API returned 403
[LocalSessionManager] Cannot initialize sessions: accountId=null, orgId=null.
[growthbook] API returned status 403   (repeated multiple times)
Turnstile iframe detected. Removing error overlay.
Blocked permission check { permission: 'media'/'background-sync'/'notifications', requestingOrigin: 'https://challenges.cloudflare.com/', ... }

Shortly after, the GPU process crashes and the app does not recover:

GPU process gone: { type: 'GPU', reason: 'crashed', exitCode: 101457950, serviceName: 'GPU' }

Note: claude.ai loads normally in a regular web browser on the same machine at the same time, which rules out a network/DNS-level block outside the app itself.

Cowork Service Log (cowork-service.log) — for reference, not the cause

Once the Windows Containers fix was applied, the VM service itself initializes and listens correctly (Service ready. Listening on \\.\pipe\cowork-vm-service), but the main app process crashes (per main.log above) before it completes a handshake with the service — sessions never get established after the fix, consistent with the app dying at the Cloudflare stage rather than any VM-service-side failure.

Additional Notes

Happy to provide full log files (ClaudeSetup.log, main.log, cowork-service.log) on request. This closely matches the symptoms described in #68674 — flagging in case it's useful as an additional data point, or let me know if this should be merged into that thread instead.

What Should Happen?

Claude Desktop should either pass the Cloudflare Turnstile challenge within the Electron webview, or fail gracefully with a retry option — rather than crashing the GPU process and becoming unusable.

Error Messages/Logs

Steps to Reproduce

1. Clean install Claude Desktop on Windows 11 25H2 via the official installer.
2. Launch the app.
3. App reaches the Cloudflare Turnstile challenge screen.
4. App crashes immediately after.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

N/A

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_