Windows 11: Terminal freezes on startup in 2.1.30/2.1.31 (regression from 2.1.29)

Bug Description

After upgrading Claude Code from version 2.1.29 to 2.1.30 or 2.1.31 on Windows 11, the terminal freezes on startup before the TUI loads. The freeze can last up to 10 minutes before eventually working.

Environment

• OS: Windows 11
• Claude Code versions tested:
• 2.1.29 - ✅ Works correctly
• 2.1.30 - ❌ Freezes on startup
• 2.1.31 - ❌ Freezes on startup
• Installation location: C:\Users\<user>\.local\bin\claude.exe

Steps to Reproduce

1. Have Claude Code 2.1.29 installed and working on Windows 11
2. Upgrade to 2.1.30 or 2.1.31
3. Run claude from any directory
4. Terminal freezes before TUI appears

Behavior

• The terminal shows npm exec tsx activity before freezing
• The freeze occurs regardless of which directory Claude is started from
• After waiting ~10 minutes, it sometimes eventually works

Troubleshooting Performed

The following did NOT resolve the issue:

1. Emptied MCP servers configuration - Set mcpServers: {} in .claude.json - still freezes
2. Deleted shell-snapshots folder - Remove-Item ~/.claude/shell-snapshots -Recurse -Force - still freezes
3. Optimized MCP server commands - Removed cmd /c npx wrappers - still freezes

Workarounds Found

1. Downgrade to 2.1.29 - Works correctly
2. Set environment variable - $env:CLAUDE_CODE_DISABLE_MCP = "1" makes startup instant (but disables MCP functionality)

Additional Notes

The fact that CLAUDE_CODE_DISABLE_MCP=1 resolves the freeze suggests the issue is related to MCP initialization, even though emptying the MCP servers configuration doesn't help. This might indicate the freeze occurs during the MCP subsystem initialization itself, before individual servers are started.

Expected Behavior

Claude Code should start without freezing, as it did in version 2.1.29.