[BUG] Cowork stuck on loading screen despite fully healthy backend VM — UI never transitions after successful SDK install (Windows 11 Pro, AMD/ASUS)

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?

Bug Report: Cowork stuck on "Setting up Claude's workspace" — UI never transitions despite fully healthy backend

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported in this exact form
• [x] This is a single bug report
• [x] I am using the latest version of Claude Desktop

System Information

• OS: Windows 11 Pro, Version 25H2 (OS Build 26200.8037)
• Claude Desktop version: latest (as of 26/03/2026)
• CPU: AMD (ASUS ROG STRIX B450-F GAMING motherboard)
• Subscription: Pro

What's Wrong?

Cowork is permanently stuck on the "Setting up Claude's workspace" loading screen. The progress bar jumps quickly to ~99% and never completes. The UI never transitions to the Cowork interface.

Critically: the backend VM is fully healthy. The cowork-service.log shows the VM starts successfully, network connects, API is reachable, and SDK installs — but the frontend never receives the ready signal.

Steps Already Taken (extensive troubleshooting)

Basic steps (did not resolve):

• Restarted PC multiple times
• Restarted Claude app multiple times
• Uninstalled and reinstalled Claude Desktop multiple times

Advanced steps taken with support:

1. Cleared VM cache via PowerShell:

Get-ChildItem "$env:LOCALAPPDATA\Packages\" -Filter "Claude_*" | ForEach-Object { Remove-Item -Recurse -Force "$($_.FullName)\LocalCache\Roaming\Claude" -ErrorAction SilentlyContinue }

1. Confirmed CoworkVMService status: Running

1. Diagnosed VHDX path mismatch — VM bundle existed at AppData\Roaming\Claude\vm_bundles but service expected it at AppData\Local\Packages\Claude_*\LocalCache\Roaming\Claude\vm_bundles. Manually copied bundle to correct location.

1. Diagnosed missing Hyper-V via event logs: [HCS] Warning: Failed to load vmcompute.dll: The specified module could not be found.

1. Enabled full Hyper-V via DISM:

dism /online /enable-feature /featurename:Microsoft-Hyper-V-All /all
dism /online /enable-feature /featurename:Microsoft-Hyper-V-Management-Clients /all
dism /online /enable-feature /featurename:Microsoft-Hyper-V-Services /all

1. Discovered SVM Mode was disabled in BIOS despite Hyper-V being enabled in Windows Features. Enabled SVM Mode in ASUS BIOS → Advanced → CPU Configuration.

1. Confirmed virtualization now enabled:

Get-WmiObject -Class Win32_Processor | Select-Object VirtualizationFirmwareEnabled
# Result: True

1. Confirmed vmcompute service now Running. vmms service does not exist.

1. Cleared UI cache (Cache, Code Cache, GPUCache folders in AppData\Roaming\Claude)

Current State of cowork-service.log (backend fully healthy)

[VM] Network status: CONNECTED
[RPC] Event: ready
[RPC] sdk-daemon is ready
[VM] sdk-daemon is ready!
[Certs] Loaded 55 CA certificates from Windows ROOT store
[RPC] API reachability: REACHABLE
[VM] API REACHABLE
[VM] Forwarding to VM: method=installSdk
[RPC] Received response: id=req-2
[VM] Installed 55 CA certificates in guest
[IdleCheck] 1 active subscribers, skipping idle check

No errors in the log. VM starts, connects, installs SDK, API is reachable — but the UI loading screen never clears.

Expected Behavior

Cowork workspace should finish loading and display the task interface.

Actual Behavior

Loading bar reaches ~99% and hangs indefinitely. The UI never transitions despite the backend being fully operational.

Hypothesis

This appears to be a bug where the frontend is not correctly receiving or handling the final "ready" event from the backend, even when the VM is fully operational. The frontend may be waiting for a specific signal or step that the backend is not sending, or the IPC between the service and the UI is broken in a one-way fashion.

Attached Logs

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

What Should Happen?

Claude cowork should launch

Error Messages/Logs

Steps to Reproduce

I try to switch to the cowork tab within claude for windows app. Not using ARM version, full version downloaded today.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Version 1.1.8629 (befdfc)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

cowork-service.log