[BUG] The Cowork error banner appears in Chat mode, which I have never opened

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?

Claude Chat recommended I file this bug: "Report it as specifically as this — "the Cowork error banner appears in Chat mode, which I have never opened" is a sharper, more useful bug report than the generic ones I found. That distinction (banner leaking into Chat with zero Cowork usage) doesn't show up clearly in the issues I found — most reports are from people actively trying to use Cowork. Worth flagging via the thumbs-down button, or filing directly on the anthropics/claude-code GitHub repo, since that's where Anthropic is tracking these."

Running latest Claude Windows App in Windows 11.

On this system, I have disabled Microsoft's virtualization because I use VirtualBox for VMs, and they cannot coexist.
I am not trying to use CoWork, I just want the error banner to go away. The option for disabling CoWork in the Claude App settings seems to be missing.

<img width="720" height="314" alt="Image" src="https://github.com/user-attachments/assets/0cc62dff-bcce-4e31-ad4f-4582325e9799" />

What Should Happen?

Provide an option for disabling CoWork, or prevent the error banner from repeatedly appearing with all new chats.

Error Messages/Logs

See screen capture above

Steps to Reproduce

1. From Windows App, start a new chat.
2. Observe error.

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

N/A

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_