[BUG] Cowork VM fails to start on macOS Tahoe 26.3.1 — VZErrorDomain Code=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?

Claude Desktop: Claude 1.4758.0 (fb266c) 2026-04-24T20:22:30.000Z
macOS Tahoe 26.3.1, Apple M4 Max

Cowork fails to start with a virtualisation error.

Failed to start Claude's workspace — Error Domain=VZErrorDomain Code=1 "The virtual machine failed to start." UserInfo={NSLocalizedFailure=Internal Virtualisation error., NSLocalizedFailureReason=The virtual machine failed to start.}

What Should Happen?

Cowork functions properly

Error Messages/Logs

Failed to start Claude's workspace — Error Domain=VZErrorDomain Code=1 "The virtual machine failed to start." UserInfo={NSLocalizedFailure=Internal Virtualisation error., NSLocalizedFailureReason=The virtual machine failed to start.}

Steps to Reproduce

Try to do anything within Claude Cowork

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.4758.0 (fb266c) 2026-04-24T20:22:30.000Z

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_