[BUG] Cowork: VM boots but guest never starts coworkd on Windows ARM64 (build 1.1.8629)

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?

Cowork on Windows ARM64 fails with "VM service not running" or "VM connection timeout after 60 seconds". The VM infrastructure (service, network, boot) works correctly, but the guest OS never initializes coworkd — the daemon log (coworkd.log) remains 0 bytes.

This is on build 1.1.8629 (Claude_1.1.8629.0_arm64__pzs8sxrjxfjjc), which appears to be the first build with native ARM64 Cowork support (the Cowork tab is enabled and cowork-svc.exe runs natively).

Environment

• OS: Windows 11 ARM64
• Claude Desktop: 1.1.8629.0 (ARM64 native, MSIX install)
• Subscription: Pro
• VirtualMachinePlatform: Enabled
• HypervisorPlatform: Enabled

What Actually Happens

Two failure modes observed:

Mode 1 — Immediate failure: "VM service not running. The service failed to start." (occurs when HypervisorPlatform was disabled)

Mode 2 — Timeout after enabling HypervisorPlatform:

• CoworkVMService starts (State: Running, ExitCode: 0)
• Network creates successfully (1ms)
• VM config creates successfully (132ms)
• VM boots successfully (140ms)
• Plan9 shares added (3ms)
• Guest connection polling begins...
• After 60 seconds: "VM connection timeout after 60 seconds"
• coworkd.log remains 0 bytes — the daemon inside the VM never starts

Diagnostic Details

Service Status

PS> Get-CimInstance Win32_Service -Filter "Name='CoworkVMService'" | Select State, ExitCode, PathName

State    ExitCode PathName
Running  0        "C:\Program Files\WindowsApps\Claude_1.1.8629.0_arm64__pzs8sxrjxfjjc\app\resources\cowork-svc.exe"

cowork_vm_node.log (key section)

2026-03-25 15:28:06 [info] [VM:steps] create_network completed (1ms)
2026-03-25 15:28:06 [info] [VM:steps] create_vm_config completed (132ms)
2026-03-25 15:28:06 [info] [VM:steps] vm_boot completed (140ms)
2026-03-25 15:28:06 [info] [VM:steps] add_plan9_shares completed (3ms)
2026-03-25 15:28:17 [info] [VM:start] Still waiting for guest connection... 10191ms elapsed, 21 polls
2026-03-25 15:28:27 [info] [VM:start] Still waiting for guest connection... 20440ms elapsed, 41 polls
2026-03-25 15:28:37 [info] [VM:start] Still waiting for guest connection... 30640ms elapsed, 61 polls
2026-03-25 15:28:47 [info] [VM:start] Still waiting for guest connection... 40777ms elapsed, 81 polls
2026-03-25 15:28:57 [info] [VM:start] Still waiting for guest connection... 50958ms elapsed, 101 polls
2026-03-25 15:29:07 [error] [VM:start] Connection timeout, last completed step: add_plan9_shares
2026-03-25 15:29:07 [error] [VM:start] Startup failed: Error: VM connection timeout after 60 seconds

cowork-service.log confirms VM boots

[VM] VM started successfully
[Console] Connected to daemon console pipe: \\.\pipe\cowork-daemon-console
[IdleCheck] 1 active subscribers, skipping idle check

coworkd.log

0 bytes — guest daemon never initializes.

Troubleshooting Attempted

• Full computer restart — no improvement
• Enabled HypervisorPlatform (was disabled) — changed error from immediate failure to 60s timeout
• Deleted VM bundle (claudevm.bundle) and re-downloaded — no improvement
• Reinstalled workspace via UI — no improvement

Analysis

The host-side infrastructure works correctly on ARM64: service runs natively, HCS creates the VM, network configures, VM boots, Plan9 shares attach. The failure is inside the guest — coworkd never starts, suggesting the rootfs or kernel in the VM bundle may not yet support ARM Hyper-V guest execution.

Related Issues

• #30864 — Feature request for ARM processor support
• #27801 — VM service not running (x64, different root cause)

What Should Happen?

Cowork workspace should start successfully.

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

1. Install Claude Desktop ARM64 (build 1.1.8629)
2. Open Cowork tab
3. Observe error: "VM service not running" or "VM connection timeout after 60 seconds"

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

1.1.8629

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_