[BUG] Claude Desktop fails to launch on Windows 11 Home 25H2 (26200.8117) — frontend never sends configure IPC to healthy CoworkVMService

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 consistently fails to launch on Windows 11 Home Single Language 25H2 (Build 26200.8117) using the MSIX package version 1.1617.0.0.

The app always shows the popup:

Claude Desktop failed to launch

This remains reproducible even after:

• updating Windows from 26200.8039 → 26200.8117
• reinstalling the MSIX package
• resetting LocalState / TempState
• validating WSL, vmcompute, and hns
• confirming healthy HCS / HCN initialization

The backend CoworkVMService is healthy, starts successfully, initializes HCS + HCN, and opens the named pipe:

\\.\pipe\cowork-vm-service

However, the frontend never completes the IPC handshake.

The key backend log line is:

Waiting for configuration from app via 'configure' method...

This strongly suggests the frontend process exits before sending the configure IPC request, while the backend remains healthy.

What Should Happen?

Claude Desktop should launch normally, complete the frontend → CoworkVMService IPC handshake, send the configure request through \\.\pipe\cowork-vm-service, and continue to the main application window without showing the launch failure popup.

Error Messages/Logs

Claude Desktop failed to launch

Windows 11 Home Single Language
25H2 (Build 26200.8117)
Claude MSIX 1.1617.0.0

Backend log evidence:
2026/04/12 05:47:47.468305 Waiting for configuration from app via 'configure' method...
2026/04/12 05:47:47.486244 [HCS] vmcompute.dll loaded successfully
2026/04/12 05:47:47.489727 [HCS] computecore.dll loaded successfully
2026/04/12 05:47:47.490996 [HCN] Initialized HCN API from computenetwork.dll
2026/04/12 05:47:47.890430 Service ready. Listening on \\.\pipe\cowork-vm-service

Steps to Reproduce

1. Use Windows 11 Home Single Language 25H2 (Build 26200.8117).
2. Install Claude Desktop MSIX version 1.1617.0.0.
3. Launch Claude Desktop from the Start menu or via AppID:

shell:AppsFolder\Claude_pzs8sxrjxfjjc!Claude

1. Observe the popup:

Claude Desktop failed to launch

1. Open:

C:\ProgramData\Claude\Logs\cowork-service.log

1. Confirm backend log shows:

Waiting for configuration from app via 'configure' method...

1. Observe that CoworkVMService remains healthy, but frontend never sends the configure IPC handshake.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

1.1617.0.0 (Claude Desktop MSIX)

Claude Code Version

1.1617.0.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Complete forensic timeline, remediation history, commands, outputs, and final root-cause proof

This issue is fully reproducible on Windows 11 Home Single Language 25H2 (OS Build 26200.8117) with Claude Desktop MSIX 1.1617.0.0.

The issue persists after full OS cumulative update, full MSIX reinstall, runtime state reset, WSL validation, VM service validation, package path validation, storage validation, and backend service log verification.

The visible user symptom is always:

```text id="i3v1ru"
Claude Desktop failed to launch

---

# A) Full environment

* OS: Windows 11 Home Single Language
* Version: 25H2
* Initial build: 26200.8039
* Updated build: 26200.8117
* Desktop package: Claude MSIX 1.1617.0.0
* Install path:
  `C:\Program Files\WindowsApps\Claude_1.1617.0.0_x64__pzs8sxrjxfjjc`
* Reproduced after cumulative update **KB5086672**
* WSL Ubuntu installed successfully
* Containers enabled
* HypervisorPlatform enabled
* VirtualMachinePlatform enabled

---

# B) Full remediation attempts already completed

## 1) Windows feature enablement

### Commands

```powershell id="h71l3g"
Enable-WindowsOptionalFeature -Online -FeatureName Containers -All
Enable-WindowsOptionalFeature -Online -FeatureName HypervisorPlatform -All
Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -All

Result

Completed successfully.

---

2) WSL backend validation

Command

```powershell id="3m66r7"
wsl --install

### Result

Ubuntu installed and launched successfully.

This validates:

* VHDX attach support
* utility VM creation
* compute backend
* virtualization path
* lightweight VM stack

---

## 3) MSIX reinstall path

### Commands

```powershell id="a5g9w9"
Stop-Process -Name claude -Force -ErrorAction SilentlyContinue
Remove-Item "$env:LOCALAPPDATA\Packages\Claude_pzs8sxrjxfjjc" -Recurse -Force -ErrorAction SilentlyContinue
Add-AppxPackage -Path "$env:USERPROFILE\Downloads\Claude.msix"

Result

Reinstall succeeded.

---

4) Local runtime DB reset

Commands

```powershell id="u3j8ko"
Remove-Item "$env:LOCALAPPDATA\Packages\Claude_pzs8sxrjxfjjc\LocalState" -Recurse -Force
Remove-Item "$env:LOCALAPPDATA\Packages\Claude_pzs8sxrjxfjjc\TempState" -Recurse -Force

### Result

Reset completed successfully.
No behavioral change.

---

## 5) Windows cumulative update validation

### Initial build

```text id="g31ytg"
26200.8039

Updated via

```text id="6xsz92"
KB5086672

### Current build proof

```powershell id="gm97ao"
winver

Output

```text id="kv8k3n"
Windows 11 Home Single Language
Version 25H2
OS Build 26200.8117

Issue still reproduces identically.

---

# C) Service and platform validation

## VM services

### Command

```powershell id="q9h1py"
Get-Service vmcompute,hns

Output

```text id="x5dt40"
Running hns
Running vmcompute

## Documents path

### Command

```powershell id="s3dw1s"
Test-Path "$env:USERPROFILE\Documents"

Output

```text id="y2kl3w"
True

## App package proof

### Command

```powershell id="r4cf9m"
Get-AppxPackage -Name *Claude | Select Name, Version

Output

```text id="z0b1nk"
Claude 1.1617.0.0

---

# D) Event Viewer evidence

Repeated Application log source:

```text id="y0bktj"
CoworkVMService

Event consistently shows service startup succeeds.

---

E) Final backend log forensic proof

Command

```powershell id="n1q8sh"
Get-Content "C:\ProgramData\Claude\Logs\cowork-service.log" -Tail 50

### Output

```text id="k2cz06"
Waiting for configuration from app via 'configure' method...
[HCS] vmcompute.dll loaded successfully
[HCS] computecore.dll loaded successfully
[HCN] Initialized HCN API from computenetwork.dll
[HCN] EnumerateNetworks result: []
[Server] Signature verification initialized
[Server] Named pipe server listening
Service ready. Listening on \\.\pipe\cowork-vm-service

This proves:

• Cowork backend healthy
• HCS healthy
• HCN healthy
• pipe server healthy
• signature validation healthy
• service lifecycle healthy

The frontend process exits before sending:

```text id="vmqz31"
configure

to:

```text id="b9trh4"
\\.\pipe\cowork-vm-service

---

F) Final validated exclusions

Already ruled out:

• broken Windows compute stack
• HCS failure
• HCN failure
• vmcompute stopped
• hns stopped
• bad MSIX registration
• stale LocalState
• stale TempState
• WSL failure
• VHDX attach issues
• Documents path issue
• app install drive redirection
• outdated Windows build
• cumulative update regression

---

Final engineering conclusion

This is now conclusively a Claude Desktop frontend IPC handshake regression on:

```text id="7uxx4v"
Windows 11 Home 25H2 build 26200.8117
Claude Desktop 1.1617.0.0

The backend CoworkVMService remains healthy and waits indefinitely, while the frontend exits before issuing the required `configure` IPC request.