Cowork folder selection shows File Picker instead of Folder Picker 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?

Description
When attempting to select a workspace folder in Cowork mode on Windows, the system opens a file selection dialog (Open File) instead of a folder selection dialog (Browse For Folder / Select Folder).
This makes it impossible to select a workspace folder, as the dialog expects a file to be selected rather than a directory.
Steps to Reproduce

Open Claude Desktop App on Windows
Start Cowork mode
Click to select a workspace folder
Observe: A file picker dialog opens (shows "Dosya adı" / "File name" field and "Tüm Dosyalar" / "All Files" filter)
Expected: A folder picker dialog should open (allowing directory selection only)

Screenshots
Screenshot 1: File picker dialog shown instead of folder picker
(The dialog shows a file selection interface with "File name" input field and "All Files" type filter, making it impossible to select a folder)
Screenshot 2: Invalid Folder Selection error
(When attempting to work around the issue, an "Invalid Folder Selection" error appears stating "The selected folder is outside your home directory" even when selecting folders within the home directory)
Expected Behavior

Cowork should open a folder/directory selection dialog (not a file selection dialog)
Users should be able to select any folder within their home directory as a workspace

Actual Behavior

A file selection dialog opens instead of a folder selection dialog
Users cannot select a folder because the dialog requires a file to be chosen
Additionally, folders outside C:\Users\<username>\ are rejected with "Invalid Folder Selection" error

Environment

OS: Windows
Claude Desktop App: Latest version
Cowork Mode: Research Preview
Language/Locale: Turkish (tr-TR)

Additional Context

The issue might be related to Windows locale or Turkish language settings
The file dialog title shows "Aç" (Turkish for "Open") which confirms it's a file-open dialog, not a folder picker
This completely blocks the use of Cowork's folder selection feature on this system

What Should Happen?

n/a

Error Messages/Logs

Steps to Reproduce

n/a

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Code version: 2.1.34

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_