[BUG] Claude Cowork not responding / spinning wheel on macOS 26.3

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?

Claude Desktop becomes completely unresponsive on launch on macOS 26.3. The app shows a spinning wheel immediately and requires force quit. This happens every time the app is opened, even after full reinstallation and clearing all cached data. The Cowork VM appears to be deadlocking the main thread, making the entire app unusable including regular chat.

What Should Happen?

Claude Desktop should launch normally and be fully responsive. Cowork should either load successfully or fail gracefully without freezing the entire application.

Error Messages/Logs

App produces no visible error on screen. Config file contained a JSON parse error on launch: Unexpected non-whitespace character after JSON at position 427 (line 16 column 2). After fixing the config, the app still becomes unresponsive. Related errors seen in other reports on this issue: VM connection timeout after 60 seconds and guest_vsock_connect timeout loop.

Steps to Reproduce

Install latest Claude Desktop on macOS 26.3
Launch the app
App immediately becomes unresponsive with spinning wheel
Force quit and relaunch, same result every time

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

I cant open the app to find out, but it is the lateset i could downloas

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_