[BUG] Title: Claude Desktop freezes on launch — VM download_and_sdk_prepare hangs indefinitely, blocks UI

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?

I used claude code CLI to investigate this issue and this was the suggested fix:

Description:

Claude Desktop (v1.1.5368) becomes completely unresponsive on every launch. The main process immediately pegs at 100%
CPU and the UI never becomes interactive.

Root cause

The download_and_sdk_prepare step during VM startup hangs indefinitely and appears to block the main Electron process.
The VM rootfs.img download never completes, and the app provides no timeout, fallback, or way to skip it.

From cowork_vm_node.log:
[VM:steps] download_and_sdk_prepare started
[downloadVM] Download already in progress, waiting...
[Bundle:status] rootfs.img missing

This pattern repeats on every launch attempt. The download never progresses or errors out.

Environment

• App version: 1.1.5368
• Platform: macOS Darwin 25.2.0, arm64 (Apple M5)
• Memory: 24GB total, ~250MB–750MB free at launch
• Network: Connected, other HTTPS requests to api.anthropic.com succeed normally

Steps to reproduce

1. Open Claude Desktop
2. App window appears but is frozen/unresponsive
3. Main process at 100% CPU indefinitely
4. Force quit and reopen — same behavior every time

What I've tried (none resolved the issue)

• Force quitting and restarting the app
• Clearing Cache, GPUCache, Code Cache, Session Storage, Local Storage, IndexedDB, and all other web caches
• Deleting vm_bundles entirely to force a clean re-download
• Making vm_bundles read-only to skip the download
• Setting coworkScheduledTasksEnabled and ccdScheduledTasksEnabled to false in config (app overwrites these on launch)

Additional errors in logs

claude.ai-web.log shows a React hydration error on every launch:
Uncaught Error: Minified React error #418

Also shows hundreds of rate_limit_event warnings being spammed rapidly in a prior session.

What Should Happen?

Suggested fix

The VM download should not block the main UI thread. If the download fails or hangs, the app should time out
gracefully and allow the user to use chat functionality without the VM/cowork features.

Error Messages/Logs

the app just spins and nothing loads.

Steps to Reproduce

Just opened the program.

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

This is the app.

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_