[Bug] Claude Desktop VM workspace startup failure: path mismatch between AppData\Roaming and AppData\Local

Bug Description

Bug Report: Claude Desktop VM Workspace Startup Failure

| Field | Details |
|-------|---------|
| Date | May 5, 2026 |
| Reporter | Frank Galarraga |
| Product | Claude Desktop (Cowork mode) v1.6259.0.0 |
| Platform | Windows 11 x64 |
| Severity | Critical - bash/workspace entirely unavailable |
| Status | Resolved (workaround applied) |

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Summary

After a Claude Desktop update, the Cowork bash/workspace sandbox failed to start on every session. The Linux VM could not be initialized, making all shell-dependent features unavailable. File tools (Read/Write/Edit) continued to function normally.

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Root Cause

A path mismatch was introduced between two components:

• Claude Desktop (the Electron/Node app) decompresses and manages VM bundle files under AppData\Roaming\Claude\vm_bundles\
• The Windows VM service (a separate native process) looks for those files under AppData\Local\Claude\vm_bundles\

These two locations diverged in the update, leaving the VM service unable to locate rootfs.vhdx at startup. The VM service also explicitly refuses to follow symlinks or junctions for security reasons, which ruled out a simple redirect.

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Errors from Logs

Error 1 (initial failure):

failed to set VHDX path: VHDX file not found:
C:\Users\**********\AppData\Local\Claude\vm_bundles\claudevm.bundle\rootfs.vhdx

Error 2 (after junction attempt):

configure: path C:\Users\***********\AppData\Local\Claude\vm_bundles
is a symlink or junction, refusing to open

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Diagnosis Steps

1. Confirmed bash workspace was returning "Workspace unavailable" on every call.
2. Reviewed Claude Desktop logs and identified the missing VHDX error pointing to AppData\Local.
3. Used file tools to verify rootfs.vhdx was present in AppData\Roaming but absent from AppData\Local.
4. Attempted a directory junction (New-Item -ItemType Junction) from Local to Roaming - rejected by VM service security check.
5. Deleted the .auto_reinstall_attempted flag so Claude Desktop could re-attempt decompression.
6. Copied all bundle files from Roaming to Local - workspace started successfully.

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Workaround Applied

Run the following in PowerShell as Administrator:

New-Item -ItemType Directory -Path "C:\Users\<user>\AppData\Local\Claude\vm_bundles\claudevm.bundle" -Force

Copy-Item "C:\Users\<user>\AppData\Roaming\Claude\vm_bundles\claudevm.bundle\*" `
  -Destination "C:\Users\<user>\AppData\Local\Claude\vm_bundles\claudevm.bundle\" -Force

Note: Replace <user> with your Windows username. This copy must be repeated after any Claude Desktop update that refreshes the VM bundle.

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Recommended Fix (Anthropic Action Required)

1. Align paths: Update either the app or the VM service so both use the same base path (AppData\Roaming or AppData\Local) consistently.
2. Auto-copy on startup: Have Claude Desktop copy or hard-link bundle files to the path the VM service expects after each decompression.
3. Update installer: Ensure the AppData\Local bundle path is populated correctly during installation and updates.

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Impact

• All Cowork bash/workspace features are unavailable until the workaround is applied.
• Affects any Windows user who installed or updated Claude Desktop after the path change was introduced.
• File tools (Read/Write/Edit) are unaffected and continue to work normally.
• The workaround must be manually re-applied after any future update that refreshes the VM bundle.

Environment Info

• Platform: win32
• Terminal: windows-terminal
• Version: 2.1.123
• Feedback ID: 59b75860-bab0-44f7-abc0-118db7e231a2