Desktop app: "Add a folder" prompt triggers logout, clears conversation/project list from UI (data confirmed intact on account via claude.ai web)

### 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?

While in an active conversation in the desktop app's Code tab, mid-task, the app unexpectedly showed an "Add a folder" prompt (never seen in months of prior use). The only option was "Open a folder." Clicking it immediately logged me out. After logging back in (via Google/Gmail), the desktop app's project/conversation list was completely empty — every prior conversation and folder was gone from the UI.

Checked Settings → Account → Active Sessions: the Desktop session shows Created and Updated both frozen at the exact moment of the incident (2026-09-08, 2:02 PM), and has not updated since, even after fully quitting the app, killing all Claude processes, and relaunching multiple times.

Critically, the data itself is not lost: signing into claude.ai in a browser (same account, separate session) shows the full, correct project/conversation list, including 2+ months of history on my main project. So this is a desktop-app-local display/sync failure, not backend data loss — but the desktop app currently cannot access it.

### What Should Happen?

The "Add a folder"/"Open a folder" flow should not force a logout or clear the visible project list. If re-authentication does happen for some reason, the desktop app should resync with the account afterward and show the real, existing project/conversation list — not an empty one.

### Error Messages/Logs

```shell
None displayed to the user at any point — the failure was silent (just an empty list after login), no error dialog or message shown.
```

### Steps to Reproduce

1. Have an active conversation in the desktop app's Code tab, mid-task (project open: a local folder, e.g. C:\Project\wyp).
2. Wait for/trigger the "Add a folder" prompt (appeared unprompted; exact trigger unknown — had not seen this prompt in months of regular use before this).
3. Click "Open a folder" (the only option presented).
4. Observe: app immediately logs out and returns to the default/sign-in screen.
5. Sign back in (Google/Gmail auth).
6. Observe: the project/conversation list in the desktop app sidebar is empty — no prior conversations or folders appear.
7. Quit the app fully, kill all Claude processes, relaunch — list remains empty.
8. Compare: sign into claude.ai in a browser with the same account — full project/conversation list appears correctly there.

### Claude Model

Sonnet (default)

### Is this a regression?

Yes, this worked in a previous version

### Last Working Version

Unknown exact version — last known-good session was immediately prior to 2026-09-08 ~2:02 PM local.

### Claude Code Version

Desktop app version: 1.49585.0

### Platform

Other

### Operating System

Windows

### Terminal/Shell

Other

### Additional Information

Account Settings → Active Sessions screenshot shows the Desktop session frozen at the incident timestamp, Chrome session current and working normally.
Organization ID consistent across both sessions (ruled out account-mismatch).
Local CLI config (~/.claude.json and backups) checked — only ever listed one project, not the source of the missing list, and unaffected.
Workaround in use: claude.ai web interface, same account, shows full history correctly.

No source file or test is identified. Start by reproducing the Windows desktop flow from the Code tab through “Open a folder,” then compare the desktop session and project list with claude.ai; done means the prompt no longer causes logout or an empty list, and re-authentication resynchronizes existing projects and conversations.

索引モデルが issue の本文から書いたものです。