[BUG]

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?

Before the Projects upgrade, my projects worked on files in a mapped network drive. Right after the upgrade, Claude inside a Project can no longer reach that drive. Regular (non-project) chats in the same app still access it fine.

Inside the Project, the thread can connect to my computer, but requesting access to T:\Pipe fails with:

A requested folder can't be granted to this session. Ask the user to connect the folder they want using the folder picker on their device, or pick a different folder.

There is no way from the Project to attach the mapped drive, so all my existing projects built on that drive are blocked.

What Should Happen?

Projects can use a mapped network drive the user approves, as they did before the upgrade and as regular chats still do. Docs say mapped drives (not UNC) are supported: https://claude.com/docs/third-party/claude-desktop/local-access#network-drives-on-windows.

Yes, it worked right before the Projects upgrade.

Error Messages/Logs

A requested folder can't be granted to this session. Ask the user to connect the folder they want using the folder picker on their device, or pick a different folder.

Steps to Reproduce

1. On Windows, map a network share to a drive letter (in my case T:\).
2. Before the Projects upgrade, a Project in Claude Desktop could work on files in T:\ without problems.
3. Update Claude Desktop to 2.19675.1 and let the Projects upgrade run.
4. Open the upgraded Project and ask Claude to work on files in T:\.
5. Claude can connect to my computer, but access to T:\ is refused with the error above. There is no folder picker in the Project to attach it.
6. In a regular chat (not in a Project), in the same app on the same machine, T:\ is still accessible.

Note: it is a regression. Everything worked right before the upgrade, and all my existing projects are built on this drive.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.16120.0 (Claude Desktop, before the Projects upgrade)

Claude Code Version

Claude Desktop 2.19675.1 (bundled Claude Code 2.1.288)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

This happens in the Claude Desktop app (Projects), not in the CLI terminal. Regular chats in the same app still access T:\. Related issues: #99554, #56636, #96810. Docs say mapped drives are supported: https://claude.com/docs/third-party/claude-desktop/local-access#network-drives-on-windows