UI freezes on first prompt submission (Windows 11)

Description

On Windows 11, Claude Code v2.1.87 freezes/blocks when the user submits their first prompt. The user can type freely, but pressing Enter to submit causes the entire client to become non-interactive for several seconds before the prompt is accepted.

Environment

• OS: Windows 11 Home 10.0.26200
• Claude Code version: 2.1.87
• Shell: Git Bash
• Auth: Claude Max (OAuth)

Reproduction

1. Open a terminal and run claude
2. Type any prompt
3. Press Enter — the client freezes for several seconds before the prompt is processed

Investigation performed

The following were systematically disabled to isolate the cause, none resolved the issue:

• All plugins (bootstrap@plugins-kit, unreal-kit@plugins-kit, update@update06) — set to false
• Remote Control for all sessions — disabled via /config
• SessionStart hooks — emptied
• UserPromptSubmit hooks (from plugin cache hooks.json) — emptied
• MCP servers (unreal-engine) — removed from enabledMcpjsonServers
• claude --bare — still freezes, ruling out hooks, LSP, plugin sync, auto-memory, CLAUDE.md auto-discovery, background prefetches, and keychain reads

Since --bare still exhibits the freeze, the issue appears to be in Claude Code's core startup/prompt-submission path rather than any user-configurable extension point.

Expected behavior

Submitting a prompt should be near-instant without a multi-second freeze.

🤖 Generated with Claude Code