[BUG] Cowork EXDEV error on Windows - MSIX virtualization causes cross-device link failure between temp and vm_bundles

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?

Environment

• OS: Windows 11 Pro (upgraded from Home)
• Claude Desktop: latest MSIX version (Claude_pzs8sxrjxfjjc)
• Hyper-V: Enabled (vmms, vmcompute both Running)
• BIOS Virtualization: Enabled

Problem

Cowork workspace setup is stuck. VM files download successfully and checksum validates, but the final rename operation always fails with EXDEV error.

Error Log

VM download failed: EXDEV: cross-device link not permitted,
rename 'C:\Users\rlno9\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\temp\wvm-XXXXXX\rootfs.vhdx'
-> 'C:\Users\rlno9\AppData\Roaming\Claude\vm_bundles\claudevm.bundle\rootfs.vhdx'

Root Cause

The MSIX app uses two different paths:

• TEMP (download): MSIX LocalCache path
• vm_bundles (destination): MSIX virtualized Roaming path

Windows MSIX virtualization treats these as different volumes, making cross-device rename impossible.

Attempted Workarounds

• Setting TEMP env variable to same directory as vm_bundles
• Creating Junction points between paths
• Setting TEMP to MSIX LocalCache path directly
• All failed because MSIX virtualization layer always treats the two paths as different devices

Expected Behavior

TEMP and vm_bundles should be on the same volume/device so rename operation succeeds.

Suggestion

Please use a single base directory for both temp download and final vm_bundles storage,
or use fs.copyFile + fs.unlink instead of fs.rename to avoid EXDEV limitation.

What Should Happen?

Cowork workspace setup should complete successfully. The VM files should download and be placed in the vm_bundles directory without any cross-device link errors. The workspace should start and be ready to use.

Error Messages/Logs

Steps to Reproduce

1. Install Claude Desktop (MSIX version) on Windows 11 Pro
2. Open Claude Desktop and click the "Cowork" tab
3. Wait for workspace setup to begin
4. Observe the progress bar stops and never completes
5. Check logs at: %LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\logs\cowork_vm_node.log
6. See repeated EXDEV error: "VM download failed: EXDEV: cross-device link not permitted"

Note: The error occurs because MSIX virtualization treats the temp download path and vm_bundles destination path as different devices, making fs.rename() fail.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.77 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_