[BUG] Previous sessions not showing in Desktop sidebar in Gateway mode (Windows) — data intact on disk, UI/indexing issue

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?

After my Claude Pro subscription expired, I switched Claude Code Desktop (Windows) to Gateway mode using a third-party inference provider. My existing projects (24 in total) no longer appear in the sidebar with their session history.

Opening a project folder manually via "New session" adds it as an entry, but only shows a blank session, none of the historical sessions for that folder load.

Data verification (confirms this is a UI/indexing issue, not data loss):

The session .jsonl files are intact on disk at:
C:\Users\faran\.claude\projects\<folder-name>\

I confirmed this across multiple project folders (e.g. D--My-Projects, etc.) — the files exist with reasonable sizes and modification dates matching real work sessions.

Separately, a third-party tool (Codex's "Import other agent setup" feature) was able to read and display full session history from the same .claude folder, confirming the source data is readable and complete, the gap is specifically in how Claude Code Desktop's sidebar indexes/displays it.

Steps to reproduce:

1. Have an existing .claude\projects\ folder with historical sessions from prior CLI/Desktop use.
2. Switch Claude Code Desktop (Windows) to Gateway mode with a third-party provider.
3. Open the sidebar, only a small subset of projects/sessions show (in my case 3 projects, 1 session each).
4. Click "New session" and browse to one of the missing project folders.
5. Observe: the project is added, but no historical sessions from the .jsonl files appear, only a fresh blank session.

Environment:

• OS: Windows
• Claude Code Desktop version: latest
• Mode: Gateway (third-party inference provider)
• Related issues: #27752, #25524, #29154, #29373, #26452, #70312, #66499 (same symptom class, this report adds the Gateway-mode angle specifically)

What Should Happen?

Have an existing .claude\projects\ folder with historical sessions from prior CLI/Desktop use.
Switch Claude Code Desktop (Windows) to Gateway mode with a third-party provider.
Open the sidebar, only a small subset of projects/sessions show (in my case 3 projects, 1 session each).
Click "New session" and browse to one of the missing project folders.
Observe: the project is added, but no historical sessions from the .jsonl files appear, only a fresh blank session.

Error Messages/Logs

Steps to Reproduce

Have an existing .claude\projects\ folder with historical sessions from prior CLI/Desktop use.
Switch Claude Code Desktop (Windows) to Gateway mode with a third-party provider.
Open the sidebar, only a small subset of projects/sessions show (in my case 3 projects, 1 session each).
Click "New session" and browse to one of the missing project folders.
Observe: the project is added, but no historical sessions from the .jsonl files appear, only a fresh blank session.

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude 1.24012.9 (03c61d) 2026-07-24T04:59:17.000Z

Platform

Other

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_