[BUG] Cowork Windows: ENOENT rename fails when AppData redirected to secondary drive via junction

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?

OS: Windows 11 Pro
Claude Desktop version: latest
Cowork VM bundle download completes successfully (checksum validated) but always fails on the rename step with ENOENT or EXDEV when AppData is on a different drive or redirected via junction.
Exact error: ENOENT: no such file or directory, rename 'D:\Temp\wvm-xxxxx\rootfs.vhdx' -> 'C:\Users\Gamer\AppData\Roaming\Claude\vm_bundles\claudevm.bundle\rootfs.vhdx'
Steps to reproduce: Install Claude Desktop on Windows with C: nearly full. Redirect TEMP and/or AppData to secondary drive. Attempt Cowork workspace setup. Download completes but rename fails every time.
Root cause: Node.js fs.rename() fails across junction boundaries and different drive letters. The fix is to use fs.copyFile() + fs.unlink() as a fallback when rename fails with ENOENT or EXDEV.
Related issues: #25476, #27801, #13476

What Should Happen?

Cowork workspace should complete setup successfully. When the VM bundle download finishes, the file should move from the temp folder to the AppData vm_bundles directory without failing. The app should use a copy and delete fallback instead of rename when the source and destination are on different drives or separated by a junction.

Error Messages/Logs

2026-03-04 15:00:54 [info] rootfs.vhdx.zst checksum validated
2026-03-04 15:00:54 [error] [download] VM download failed: ENOENT: no such file or directory, rename 'C:\Users\Gamer\AppData\Local\Temp\wvm-bL1nId\rootfs.vhdx' -> 'C:\Users\Gamer\AppData\Roaming\Claude\vm_bundles\claudevm.bundle\rootfs.vhdx'

2026-03-04 15:14:58 [info] rootfs.vhdx.zst checksum validated
2026-03-04 15:14:59 [error] [download] VM download failed: ENOENT: no such file or directory, rename 'C:\Users\Gamer\AppData\Local\Temp\wvm-bL1nId\rootfs.vhdx' -> 'C:\Users\Gamer\AppData\Roaming\Claude\vm_bundles\claudevm.bundle\rootfs.vhdx'

Failed to start Claude's workspace
EXDEV: cross-device link not permitted, rename 'D:\Temp\wvm-7lTeOx\rootfs.vhdx' -> 'C:\Users\Gamer\AppData\Roaming\Claude\vm_bundles\claudevm.bundle\rootfs.vhdx'

Steps to Reproduce

1. Install Claude Desktop on Windows 11 Pro with C: drive nearly full (under 10GB free)
2. Migrate user data to secondary drive (D:) to free space
3. Redirect AppData to D: via NTFS junction: mklink /J "C:\Users\[user]\AppData\Roaming\Claude" "D:\Claude-AppData"
4. Set TEMP/TMP environment variables to D:\Temp
5. Open Claude Desktop and navigate to Cowork tab
6. Click Download or Reinstall Workspace
7. Download completes and checksum validates successfully
8. Rename step fails with ENOENT or EXDEV error
9. VM bundle is deleted and process repeats indefinitely

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.68 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

This is a Cowork (Claude Desktop) issue, not Claude Code CLI. Claude Code version field does not apply.

Additional context:

• C: drive was nearly full (under 3GB free) which caused initial download failures
• Freed ~44GB by uninstalling apps and clearing temp files
• Tried multiple approaches: junction point, moving TEMP to D:, Defender exclusions
• Download consistently completes and checksum validates successfully
• Only the final rename/move step fails
• Issue persists regardless of whether TEMP is on C: or D:
• Claude Desktop version: 1.1.4498.0
• Debug logs submitted via in-app log sharing