[BUG] Cowork fails with HRESULT 0x80310000 when second physical drive is BitLocker-locked — hard failure with no fallback

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 fails to start with HRESULT 0x80310000 (FVE_E_LOCKED_VOLUME) because it attempts to add a Plan9 share for every lettered drive on the system, including drives that are BitLocker-locked and intentionally inaccessible. There is no graceful fallback — the entire workspace fails hard.

In my case, I have two physical drives:

• C: — my personal drive (Windows installation, BitLocker unlocked)
• D: — another windows installation drive (BitLocker-locked, inaccessible by design)

Cowork attempts to share D: into the VM, hits the BitLocker lock, and aborts entirely. Reinstalling the workspace does not resolve the issue because the root cause is the drive enumeration logic, not the bundle.

This is also a privacy and security concern: Cowork should not be trying to access another drive without permission and it should be able to function without that access.

What Should Happen?

Cowork should either:

• Only share drives the user explicitly selects or consents to, OR
• Gracefully skip drives that are inaccessible rather than failing the entire workspace startup

Error Messages/Logs

**Error displayed in Claude Desktop:**

Failed to start Claude's workspace
failed to add Plan9 share 'd': HcsWaitForOperationResult failed with HRESULT 0x80310000: {"Error":-2144272384,"ErrorMessage":""}


**From cowork_vm_node.log:**

2026-04-07 22:01:18 [info] [VM:steps] add_plan9_shares started
2026-04-07 22:01:19 [error] [VM:start] VM boot failed: failed to add Plan9 share 'd': HcsWaitForOperationResult failed with HRESULT 0x80310000: {"Error":-2144272384,"ErrorMessage":""}
2026-04-07 22:01:19 [info] [VM:start] Skipping auto-reinstall (already attempted once)


**Root cause confirmed via manage-bde:**

manage-bde -status D:

Lock Status:       Locked
Protection Status: Unknown
Encryption Method: XTS-AES 256


HRESULT 0x80310000 = FVE_E_LOCKED_VOLUME ("This drive is locked by BitLocker Drive Encryption.")

Steps to Reproduce

1. Have a Windows machine with two physical drives, both with BitLocker enabled
2. Have the second drive (D:) locked/inaccessible
3. Install Claude Desktop and open the Cowork tab
4. Workspace fails immediately at the add_plan9_shares step

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

unknown

Claude Code Version

v1.1062.0.0 (MSIX)

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

• C: drive BitLocker status: Unlocked, Protection On, XTS-AES 128, 100% encrypted
• D: drive BitLocker status: Locked, XTS-AES 256
• Attempted fixes that did not resolve the issue: restarting Claude, restarting computer, reinstalling workspace, running icacls to grant SYSTEM full permissions on the Claude MSIX package folder
• Related issues with same error but root cause not previously identified: #43452, #43070, #43482