[BUG] [Claude Desktop] [Cowork] Cowork sandbox cannot access local project folders on macOS

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?

Bug: Cowork sandbox cannot access local project folders on macOS

What's Wrong?

Cowork cannot access local project folders specified in the Claude Desktop sidebar, even though the folder exists and Full Disk Access has been granted to Terminal.app and Claude Desktop.

Local path attempted: /Users/jeffmcknight/ClaudeProjects/EnhancedGeothermal

Environment

• macOS version: 15.6.1
• Claude Desktop version: 2.2553.13 (16e20e)
• Release date: 2026-09-21T20:31:17.000Z
• Platform: macOS (Apple Silicon or Intel)
• Subscription plan: [Pro/Max/Team]

Root Cause

Cowork runs in a sandboxed Linux VM container. The additionalDirectories configuration (if applicable) or sidebar folder selection is not being properly mounted into the container's sandbox profile, preventing the Read tool from accessing files outside the hardcoded allowed paths.

Related Issues

• #29013 (additionalDirectories not granting Read access)
• #22628 (sandbox write paths hardcoded)
• #54744 (TCC-dependent Scheduled Tasks)

Workaround

Use Claude Code CLI instead:

cd /Users/jeffmcknight/ClaudeProjects/EnhancedGeothermal
claude

This works correctly with local files without the Desktop app's sandbox constraints.

Additional Context

Files are ready in the container at /mnt/project/, suggesting the mount was attempted but the filesystem permissions within the sandbox are blocking access to the host path.

What Should Happen?

What Should Happen?

When a local folder is selected in the Cowork sidebar, Claude should be able to read files from that path within a Cowork session.

Error Messages/Logs

**Error message:**
`That path isn't accessible from this container environment. I'm running in a sandboxed container without direct access to your Mac's local filesystem.`


Claude can see files in the container's `/mnt/project/` but cannot read from the actual macOS path provided.

Steps to Reproduce

Steps to Reproduce

1. Open Claude Desktop on macOS
2. Switch to Cowork tab
3. Select a local folder via the folder picker (e.g., /Users/jeffmcknight/ClaudeProjects/EnhancedGeothermal)
4. Start a new Cowork session
5. Attempt to read or reference files from that folder
6. Claude responds that the path is not accessible from the container

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Desktop version: 2.2553.13 (16e20e)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_