[BUG] BUG: Cannot add UNC network path as project folder on Windows

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?

Environment: Windows 10, Claude Code Desktop

Problem:
When trying to add a new UNC path (\\server\share\folder) as a project folder in Claude Code,
the error "네트워크(UNC) 경로는 여기서 지원되지 않습니다" appears and the folder cannot be added.

Current path in use (works): \\main\월드원서버\4. KTR통보문
New path (fails): another UNC path on the same server

Expected behavior: UNC paths should be addable as project folders, as they were previously.

Related issues: #45297, #29935, #44152

What Should Happen?

UNC paths (\server\share\folder) should be addable as project folders in Claude Code on Windows, as they were previously supported.

Error Messages/Logs

Steps to Reproduce

Open Claude Code Desktop on Windows
Click "Add Project Folder" (or equivalent button to add a new project)
Enter or browse to a UNC network path (e.g. \\server\share\folder)
Confirm the selection
Error appears: "네트워크(UNC) 경로는 여기서 지원되지 않습니다" (Network UNC paths are not supported here)
Note: The same UNC path format (\\main\월드원서버\4. KTR통보문) was previously added successfully and still works as an existing project. Only adding new UNC paths is blocked.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.81

Claude Code Version

2.1.81

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_