[BUG] Cowork stuck on "Authenticating..." forever — Mac16,10 (M4 Mac mini 2024), macOS Tahoe 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?

Cowork permanently stuck on "Authenticating..." and never progresses. Same Anthropic account works fine on iMac21,1 with same OS.

What Should Happen?

Steps already tried:

Full reinstall
Cleared keychain, vm_bundles, cache
Reset all TCC permissions
Firewall inactive, VPN inactive
Claude never appears in Local Network privacy list

Error Messages/Logs

Key finding from logs:

Repeated Trust evaluate failure: [leaf MissingIntermediate] in system logs. VM starts (com.apple.Virtualization.VirtualMachine launches) but authentication never completes. No cowork_vm_node.log is ever written.

Steps to Reproduce

Environment:

Hardware: Mac16,10, Apple M4, 16GB RAM
OS: macOS Tahoe 26.4.1 (25E253)
No MDM/DEP enrollment
SIP enabled
Virtualization entitlement confirmed present

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

1.4758.0

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_