[BUG] "1.3036.0 — cowork session crashes with exit code 1 on macOS 26.4.1"

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?

Summary

After updating to Claude 1.3036.0 (cf521c, built 2026-04-16T16:17:33Z), the Claude Code desktop app crashes immediately with "Claude Code process exited with code 1" in every code-mode session on a previously working project. No session was able to start successfully after the update.

Environment

• Claude version: 1.3036.0 (cf521c) 2026-04-16T16:17:33.000Z
• macOS: 26.4.1 Tahoe (Build 25E253)
• Hardware: MacBook Pro, Apple Silicon
• Previous state: Claude Code was working normally before this update. The session had been long-running (multiple days), active on a large project (~1,500 commits, ~1.5 GB repo, heavy PDF/image extraction pipelines, custom MCP usage).

Repro

1. Install Claude Code update 1.3036.0 (automatic, delivered 2026-04-16).
2. Open existing project in code mode.
3. Any action — new prompt, resume conversation, navigate files — produces the error banner:

> ⚠ Something went wrong
> Claude Code process exited with code 1
> You can restart the conversation from an earlier message.

What I tried (none fixed it)

• grep -i anthropic ~/.zshrc ~/.zprofile ~/.bash_profile — no ANTHROPIC_API_KEY set anywhere
• echo $ANTHROPIC_API_KEY — empty
• Moved ~/Library/Application Support/Claude/claude-code-sessions/ out of the way (session cleanup)
• Full quit (Cmd+Q) and restart of Claude Code
• Confirmed no managed-mcp.json present

Notes

• This matches the pattern of #8557 ("VS Code extension — process exited with code 1 since update") and #36419 ("code mode crashes instantly, VM never boots").
• The crash started immediately after the 1.3036.0 update. Prior build (whatever shipped before today) worked fine on the same project with identical environment.
• Screenshot attached below.

Screenshot

[drag and drop your screenshot here — GitHub will insert it automatically]

What Should Happen?

After clicking retry, it should just work

Error Messages/Logs

Steps to Reproduce

Click on the Cowork tab. Open a new task, or click on an existing one. The error message comes up right away. Even if I just type 'ping'

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.3036.0 (cf521c) 2026-04-16T16:17:33.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

<img width="1161" height="790" alt="Image" src="https://github.com/user-attachments/assets/166351d5-c111-40a7-afec-89fe5e96a37d" />