[BUG] Claude Desktop SSH: "Host denied (verification failed)" on Windows — VM never starts (isGuestConnected: false)

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?

SSH connection always fails with "Host denied (verification failed)" in Claude Desktop on Windows. The internal VM never starts (isGuestConnected: false in vm-info.json). The known_hosts file at the expected location exists but is ignored by the app.

What Should Happen?

The VM should start on app launch and the SSH connection should complete successfully.

Error Messages/Logs

2026-04-16 [warn] Host <REMOTE_IP>:<CUSTOM_PORT> is not in known_hosts
2026-04-16 [error] Connection error: Host denied (verification failed)
2026-04-16 [error] Connection failed: Host denied (verification failed)

vm-info.json: "isGuestConnected": false (at every launch)

Steps to Reproduce

1. Open Claude Desktop on Windows 11
2. Go to Code tab > New SSH connection
3. Fill in: host <USERNAME>@<REMOTE_IP>, port <CUSTOM_PORT>, identity file path
4. Click connect
5. Error: "Host denied (verification failed)"

Note: Direct SSH from PowerShell works perfectly with the same credentials.
Hyper-V is enabled. known_hosts manually populated. KEX algorithms restricted on server. Nothing resolves the issue.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.2773.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Related issues: #26809, #25659, #35073
Attaching ssh.log and cowork_vm_node.log.

cowork_vm_node.log

ssh.log