[BUG] Connected folders never mount inside VM — host reports Plan9 share added successfully, guest sees none

### Preflight Checklist

- [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) 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

• Claude Desktop 1.49585.0, Electron 44.2.0, Node 24.20.0


• Windows 11 Home, build 26200 (25H2)


• Framework Laptop 13, 12th Gen i5-1240P, 32 GB RAM


• C: 237.4 GB used / 1,668.3 GB free


• VM bundle freshly downloaded 2026-09-09 (9.01 GB, verified complete)

Summary

The Cowork VM boots successfully and reaches full health, but no connected folder is ever mounted inside it. Any shell command fails before running, with:

sandbox-helper: no Plan9 drive shares mounted under /mnt/.virtiofs-root/shared

All connected folders fail together, consistent with the single c -> C:\ root share never mounting in the guest. Host-side file operations (list / stage / commit) work normally throughout.

Host log shows complete success

C:\ProgramData\Claude\Logs\cowork-service.log:

18:06:05.797828 [VM] Plan9 share added: c -> C:\ (port=9902, readOnly=false)

18:06:06.049771 [HCS] HcsStartComputeSystem returned: hr=0x0

18:06:06.145425 [VM] Adding Plan9 share via HcsModifyComputeSystem: name=c path=C:\ port=9902 flags=0x10 hasToken=true

18:06:06.145425 [HCS] HcsModifyComputeSystem returned: hr=0x0

18:06:21.700306 [VM] VM started successfully

18:06:24.338784 [RPC] sdk-daemon is ready

18:06:26.073355 [VM] Installed 66 CA certificates in guest

18:06:26.266356 [RPC] API reachability: REACHABLE

No error appears anywhere. The host completes its entire sequence, including API reachability: REACHABLE, while the guest has nothing mounted.

Ruled out

Additional observation

The app's own logs (...\LocalCache\Roaming\Claude\logs\) have not been written since 2026-08-20 19:48, across at least three app versions. There is a dangling latest symlink in that folder that Copy-Item cannot resolve; removing it did not restore logging. This may be a symptom rather than a separate issue — a guest that can't mount its filesystem view plausibly can't log either.

Impact

device_bash is entirely unavailable. File staging and committing still work, so the session remains usable for file operations at reduced speed.

Possibly related: #60631, #64592, #45883, #56145, #55404

### What Should Happen?

Connected folders mount inside the VM under $HOME/mnt/, and shell
commands can read and write them.

### Error Messages/Logs

```shell

```

### Steps to Reproduce

1. On Windows, connect one or more local folders to a Cowork session.
2. Open Claude Desktop and let the workspace start.
3. Confirm the VM booted successfully — C:\ProgramData\Claude\Logs\cowork-service.log
ends with "[RPC] API reachability: REACHABLE".
4. Run any shell command in the session (e.g. `ls`).
5. The command never executes.

Note on reproducibility: onset was spontaneous rather than triggered by a specific
action. Once in this state it is 100% reproducible on every call, and persists across:
- restarting the desktop app
- stopping and starting CoworkVMService
- a full Windows restart
- deleting vm_bundles and re-downloading the complete 9.01 GB image

### Claude Model

Not sure / Multiple models

### Is this a regression?

I don't know

### Last Working Version

_No response_

### Claude Code Version

Claude Desktop 1.49585.0

### Platform

Anthropic API

### Operating System

Windows

### Terminal/Shell

PowerShell

### Additional Information

_No response_

Start with C:\ProgramData\Claude\Logs\cowork-service.log and the guest sandbox-helper mount check. Trace the Plan9 share from "Plan9 share added" through HcsModifyComputeSystem and compare it with the guest path $HOME/mnt/. Done means connected folders mount in the VM and commands such as `ls` can read and write them.

Vom Indexierungsmodell aus dem Issue-Text verfasst.