claude-code - 💡(How to fix) Fix PowerShell output displays garbled text on Windows when system codepage is Big5 (950) [1 comments, 2 participants]

Description

On Windows systems with system codepage set to Big5 (950), Claude Code executing PowerShell commands produces garbled output for multi-byte characters (Japanese, Traditional Chinese, Korean, etc.). This affects user experience in non-English regions.

Environment

• OS: Windows 11 Pro 10.0.26200
• System Codepage: 950 (Big5)
• Shell: Git Bash (MSYS2)
• Claude Code Version: v2.x

Steps to Reproduce

1. Install Claude Code on Windows
2. Execute PowerShell command with multi-byte characters:

   powershell.exe -NoProfile -Command "Write-Host 'テスト中文'"

3. Expected output: テスト中文
4. Actual output: garbled text (e.g., �����)

Current Workaround

This can be resolved by creating a wrapper script:

# Create pwshutf8 wrapper
#!/bin/bash
powershell.exe -NoProfile -Command "[Console]::OutputEncoding=[Text.Encoding]::UTF8;$OutputEncoding=[Text.Encoding]::UTF8; $1"

However, this is not an ideal solution as it requires manual configuration by users.

Proposed Solutions

Option 1: Add Configuration Setting

Add encoding-related configuration to settings.json:

{
  "shell": {
    "powershell": {
      "encoding": "utf-8"
    }
  }
}

Option 2: Automatic Detection and Setting

Claude Code automatically detects system codepage and sets correct output encoding when executing PowerShell commands.

Option 3: Change Default Behavior

Default to UTF-8 encoding, with Big5 as fallback.

Impact

• All Claude Code users on Windows in non-English regions (using Big5, EUC-KR, etc.)
• Users who use PowerShell as their primary shell

Additional Notes

• This is not a Claude Code bug, but a system-level limitation of the Windows + PowerShell + Git Bash combination
• Changing system codepage affects other applications (e.g., default CSV file opening)
• Reference: https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_output_formats