[BUG] Cowork (Windows): a project's Recents lists sessions belonging to OTHER projects — opening one mounts the wrong working folder + CLAUDE.md (post-unification)

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?

In the Cowork desktop app, a project's Recents list displays sessions that belong to OTHER Cowork projects. Opening one loads a session parented under a different project entirely, with that other project's working folder and CLAUDE.md mounted instead of the one whose Recents I clicked from. This is not only a display bug — the mis-listed session executes against the wrong project's folder and instructions.

Steps to reproduce:

1. Have multiple Cowork projects created independently alongside same-named Chat projects before the Chat/Cowork merge.
2. Open Cowork Project A's project view and look at its Recents list.
3. Click a session shown in that list.

Actual: The session belongs to a different project. Opened from Project A's view, the breadcrumb renders as "Project C (Chat) / Project B (Cowork) / [session name]". The Working Folders panel shows Project B's folder and files mounted, and the session reads Project B's CLAUDE.md. Project A's correctly configured Context is ignored.

Impact: Sessions launched or resumed from a project's Recents can silently run against the wrong project's instructions and data. In my case a workflow session read the wrong CLAUDE.md and executed with missing and incorrect context. With folder write access granted, this is an execution and data-integrity risk, not just a display glitch.

Environment:

• Claude Desktop, Windows 11, Microsoft Store (MSIX) build
• Max plan
• Multiple projects set up as independent Chat + Cowork twins (same names) before the merge

Notes:

• Each project's Context panel is configured correctly and distinctly (correct linked chat project, working folder, files). The defect is session-to-project association / Recents scoping, not configuration.
• Desktop logs show [Spaces] Loaded 5 spaces correctly, so the spaces exist; the session-to-project mapping is what's wrong.
• Appears part of the post-unification Cowork Recents/session-mapping regression cluster: #79422, #78981, #79434, #76604.
• #76573 reports a project's founding folder being wrongly auto-mounted into sessions; this issue is a cross-project extension of that — the mounted folder belongs to a different project entirely.

Workaround: Avoid launching or resuming from Recents. Run a pre-flight before giving any session work: "State your working folder path and the first line of the CLAUDE.md you loaded. Do not proceed." Kill and relaunch if either is wrong.

What Should Happen?

Opening a session from Project A's Recents should load a session that belongs to Project A, mounting Project A's configured working folder and CLAUDE.md. A project's Recents list should be scoped to that project's own sessions, and a session's breadcrumb, mounted folder, and instructions should all match the project it was opened from.

Error Messages/Logs

[Spaces] Loaded 5 spaces for <account>/<org>

Steps to Reproduce

1. Have multiple Cowork projects that were created independently alongside same-named Chat projects before the Chat/Cowork merge.
2. Open Cowork Project A's project view and look at its Recents list.
3. Click a session shown in that list.
4. Observe: the opened session belongs to a different project (Project B), the breadcrumb reads "Project C (Chat) / Project B (Cowork) / [session]", and the Working Folders panel shows Project B's folder and CLAUDE.md mounted rather than Project A's.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Worked before the Chat/Cowork merge rollout (~July 8, 2026). Exact prior version number not recorded.

Claude Code Version

N/A — this is a Cowork desktop app bug, not the CLI. Claude Desktop (Microsoft Store / MSIX build).

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

This is a Cowork desktop app defect, not a Claude Code CLI bug — filing here since Cowork desktop bugs are tracked in this repo (e.g. #76573, #79434).