[BUG] Cowork on Windows ARM64 (Snapdragon) - 3-stage VM failure chain fully reproduced (vhdx copy, service start, HNS network)

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?

aReporting a fully reproduced, 3-stage Cowork VM failure chain on Windows 11 ARM64 (Snapdragon), confirmed step by step over an extended debugging session.

Device: Windows 11 ARM64 (Snapdragon). Claude Desktop 1.25927.0.0 (arm64 MSIX, package Claude_1.25927.0.0_arm64__pzs8sxrjxfjjc).

STAGE 1 - vhdx never copied out of the read-only AppX directory (matches #45549): smol-bin.arm64.vhdx existed only under C:\Program Files\WindowsApps\...\app\resources. No .vhdx existed anywhere under %LOCALAPPDATA%\Claude\vm_bundles. Error shown: "VM connection timeout after 60 seconds". Manually copying the file to %LOCALAPPDATA%\Claude\vm_bundles\claudevm.bundle\smol-bin.vhdx (renamed from smol-bin.arm64.vhdx) changed the error, confirming this was the first blocker.

STAGE 2 - CoworkVMService not running: after the Stage 1 workaround, new error: "VM service not running. The service failed to start." Get-Service CoworkVMService showed Stopped. Manually running Start-Service CoworkVMService started it successfully with no error.

STAGE 3 - HNS network never created: after Stage 2, error reverted to "VM connection timeout after 60 Also matches #69901 ("Four Compounding Failures" - also closed/locked, could not comment there either).seconds". Get-HnsNetwork shows only the default "Default Switch" (ICS) - no Cowork/Claude-specific HNS network is ever created.

Windows virtualization prerequisites verified correct throughout: VirtualMachinePlatform Enabled, hns and vmcompute services Running, bcdedit hypervisorlaunchtype Auto, Windows Firewall Hyper-V rules allowing. Local antivirus (ESET) network filter services were also stopped as a test with no change in Stage 3 behavior.

Related existing reports, each apparently capturing only one stage of the same underlying chain on ARM64: #45549, #46516, #39636, #67901. Filing as a new report since #45549 is closed and locked.

What Should Happen?

Cowork should initialize successfully on Windows ARM64: the vhdx should be copied to a writable location on first launch, CoworkVMService should start automatically and stay running, and the Cowork-specific HNS network should be created so the guest VM can connect.

Error Messages/Logs

a"VM connection timeout after 60 seconds" (initial and final state)
"VM service not running. The service failed to start." (intermediate state, after Stage 1 workaround)

Get-Service CoworkVMService -> Stopped (before manual Start-Service)
Get-HnsNetwork -> only "Default Switch" (ICS), no Cowork-specific network
smol-bin.arm64.vhdx present only at C:\Program Files\WindowsApps\Claude_1.25927.0.0_arm64__pzs8sxrjxfjjc\app\resources\smol-bin.arm64.vhdx, absent from %LOCALAPPDATA%\Claude\vm_bundles

Steps to Reproduce

1. Install/run Claude Desktop (arm64 MSIX) on a Windows 11 ARM64 device (Snapdragon).
2. Open Cowork and try any task requiring the sandbox.
3. 3. Observe "VM connection timeout after 60 seconds".
4. 4. Check C:\Program Files\WindowsApps\Claude_<version>_arm64__pzs8sxrjxfjjc\app\resources\smol-bin.arm64.vhdx exists, but no .vhdx exists under %LOCALAPPDATA%\Claude\vm_bundles.
5. 5. As a workaround, manually create %LOCALAPPDATA%\Claude\vm_bundles\claudevm.bundle\ and copy smol-bin.arm64.vhdx there as smol-bin.vhdx. Relaunch Claude and retry Cowork -> error changes to "VM service not running. The service failed to start."
6. 6. Run Get-Service CoworkVMService -> shows Stopped. Run Start-Service CoworkVMService -> starts without error.
7. 7. Retry Cowork -> error reverts to "VM connection timeout after 60 seconds". Run Get-HnsNetwork -> only the default "Default Switch" (ICS) exists, no Cowork-specific network was created.

Claude Model

None

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Desktop 1.25927.0.0 (arm64)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_