Claude Code CLI fails on Windows when username path contains spaces

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?

Claude Code CLI fails to start or behaves unexpectedly on Windows when the
user profile path contains spaces (e.g., C:\Users\Mario Rossi\).

This was previously reported in issue #31418 (now locked). The issue
persists and has not received an official fix or acknowledgment.

The only working solution found by affected users is setting the
CLAUDE_HOME environment variable to a path without spaces
(e.g., C:\ClaudeHome\).

What Should Happen?

Claude Code CLI should start and operate normally regardless of whether
the Windows username or profile path contains spaces.

Error Messages/Logs

Claude Code fails to initialize. Error related to path resolution 
when USERPROFILE or APPDATA contains spaces.

Steps to Reproduce

1. Install Claude Code CLI on Windows with a username containing spaces

(e.g., "Mario Rossi", resulting in C:\Users\Mario Rossi\)

1. Run claude from any directory (without setting CLAUDE_HOME)
2. Observe that Claude Code fails to start or behaves unexpectedly
3. Set environment variable CLAUDE_HOME=C:\ClaudeHome\ (path without spaces)
4. Run claude again — it works correctly

Note: This issue was previously reported in #31418 (now locked without a confirmed fix).

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.71 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

The workaround is to set the CLAUDE_HOME environment variable to a path
without spaces (e.g., CLAUDE_HOME=C:\ClaudeHome\). This allows Claude Code
to start and work normally.

This issue affects all Windows users whose Windows username contains a space,
which is extremely common (e.g., "Nome Cognome"). A native fix or official
documentation of the CLAUDE_HOME workaround would benefit many users.

Reference: #31418 (closed and locked without confirmed fix)