[BUG] Force quitting Claude Code during auto-update prevents CLI from launching

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?

When Claude Code is force quit during an auto-update process, the claude command in the terminal becomes non-functional. Attempting to run claude after this occurs fails to launch the application, leaving the CLI in an unusable state.

What Should Happen?

Even if Claude Code is force quit during an auto-update, the claude command should either:

Complete the update process on next launch and function normally, or
Detect the incomplete update state and automatically recover/repair itself, or
Display a clear error message with instructions on how to fix the installation

The CLI should remain accessible and functional, or provide a clear path to recovery.

Error Messages/Logs

Steps to Reproduce

1. Have Claude Code installed and working (verify with claude --version)
2. Wait for or trigger an auto-update process to begin
3. While the update is in progress, force quit Claude Code (e.g., quit via ctrl+C)
4. Open a new terminal window
5. Attempt to run the claude command
6. Expected result: Command launches successfully or shows recovery instructions

Actual result: Command fails to launch or becomes unresponsive

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.26

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_