Cowork not working -- Virtual Machine not loading

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 Code native app (2.1.83) fails to start the workspace VM on macOS Darwin 25.0.0 (macOS 16 beta) with:

> Error Domain=VZErrorDomain Code=1 "The virtual machine failed to start." UserInfo={NSLocalizedFailure=Internal
Virtualization error., NSLocalizedFailureReason=The virtual machine failed to start.}

## Environment

• Claude Code version: 2.1.83 (native)
• OS: macOS Darwin 25.0.0 (macOS 16 beta)
• Model: claude-sonnet-4-6
• CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC is set (auto-updates disabled)

## Steps to Reproduce

1. Open Claude Code (native desktop app)
2. Start a new session
3. Workspace VM fails to start — error dialog appears with VZErrorDomain Code=1

## /doctor Output

• Currently running: native (2.1.83)
• Search: OK (bundled)

## Additional Context

• Restarting Claude Code does not resolve the issue
• The error occurs before session initialization completes, so debug logging does not capture it (debug log from a

successful CLI session attached below for reference)

• This may be a Virtualization.framework compatibility issue on macOS 16 beta

## Debug Log (successful CLI session for reference)

2026-04-16T13:24:26.881Z [DEBUG] Started caffeinate to prevent sleep
2026-04-16T13:24:26.883Z [DEBUG] AutoUpdaterWrapper: Installation type: native
2026-04-16T13:24:26.884Z [DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
2026-04-16T13:24:26.884Z [DEBUG] LSP Diagnostics: Checking registry - 0 pending
2026-04-16T13:24:26.884Z [DEBUG] Hooks: Found 0 total hooks in registry
2026-04-16T13:24:26.884Z [DEBUG] Sending 73 skills via attachment (initial, 42 total sent)
2026-04-16T13:24:26.884Z [DEBUG] Skill prompt: showing "hookify:writing-rules" (userFacingName="Writing Hookify
Rules")
2026-04-16T13:24:26.884Z [DEBUG] Hooks: checkForNewResponses returning 0 responses
2026-04-16T13:24:26.885Z [DEBUG] Getting matching hook commands for UserPromptSubmit with query: undefined
2026-04-16T13:24:26.885Z [DEBUG] Found 1 hook matchers in settings
2026-04-16T13:24:26.885Z [DEBUG] Matched 1 unique hooks for query "no match query" (1 before deduplication)
2026-04-16T13:24:26.914Z [DEBUG] StatusLine completed with status 0
2026-04-16T13:24:26.965Z [DEBUG] Hook UserPromptSubmit (UserPromptSubmit) success: {}
2026-04-16T13:24:26.967Z [DEBUG] autocompact: tokens=4293 threshold=167000 effectiveWindow=180000
2026-04-16T13:24:26.968Z [DEBUG] Dynamic tool loading: 0/25 deferred tools included
2026-04-16T13:24:26.969Z [DEBUG] attribution header x-anthropic-billing-header: cc_version=2.1.83.c50;
cc_entrypoint=cli
2026-04-16T13:24:29.611Z [WARN] [3P telemetry] Event dropped (no event logger initialized): api_request
2026-04-16T13:24:34.347Z [DEBUG] Hook output does not start with {, treating as plain text
2026-04-16T13:24:34.347Z [DEBUG] Hook PreToolUse:Bash (PreToolUse) success:
grep: repetition-operator operand invalid

What Should Happen?

Opening Claude Code and starting a new session should successfully start the workspace VM and land in a working
session without errors.

Error Messages/Logs

Error Domain=VZErrorDomain Code=1 "The virtual machine failed to start." UserInfo={NSLocalizedFailure=Internal        
  Virtualization error., NSLocalizedFailureReason=The virtual machine failed to start.}

Steps to Reproduce

1. Install Claude Code native app version 2.1.83 on macOS Darwin 25.0.0 (macOS 16 beta)
2. Open the Claude Code desktop app
3. Start a new session
4. Observe: workspace VM fails to start with VZErrorDomain Code=1 error dialog
5. Click OK on the error dialog
6. Repeat steps 2-4 — error is consistent across restarts

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

❯ last worked early yesterday 4/15/26

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

• CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC env var is set, disabling auto-updates
• CLI mode (running claude in terminal) works normally — only the native desktop app workspace VM fails
• /doctor output: "Currently running: native (2.1.83), Search: OK (bundled)"
• Issue is specific to the Virtualization.framework (VZErrorDomain) — not a hook, config, or auth issue
• macOS 16 is pre-release; this may be a Virtualization.framework regression in a recent beta build