[BUG] Cowork/Code session auth fails after March 25 outage - "sign-in expired" loop on macOS 26.3.1

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?

After the March 25, 2026 Anthropic service outage, Cowork and Claude Code both fail to start with the error:

"Unable to start session: account information is unavailable because your sign-in has expired. Please sign in to the desktop app again."

The VM progress bar loads to completion, then immediately fails at the authentication step. Signing out and back in does not resolve the issue. The web version (claude.ai) works normally with the same account.

This was working normally before the March 25 outage.

What Should Happen?

Cowork and Code sessions start normally after sign-in, as they did before March 25.

Error Messages/Logs

Error invoking remote method '$eipc_message$_9875eed2-fde6-4f29-aaca-86905e69e002_$_claude.web_$_LocalSessions_$_start': Error: Unable to start session: account information is unavailable because your sign-in has expired. Please sign in to the desktop app again.

System log shows repeated:
XPC_ERROR_CONNECTION_INTERRUPTED
Re-initialization successful; calling out to event handler with XPC_ERROR_CONNECTION_INTERRUPTED

Steps to Reproduce

1. Open Claude Desktop (latest version)
2. Sign in with Google account (Max plan)
3. Click Cowork tab
4. Select or create a project
5. Progress bar loads to 100%, then fails with "sign-in expired" error
6. Same error occurs in Code tab

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

arch 25, 2026 (before outage)

Claude Code Version

2.1.78 (Claude Desktop built-in)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

macOS 26.3.1 (Tahoe), Apple M4
Max plan, Gmail/Google OAuth login
Web version works normally, only Desktop Cowork/Code affected
Issue started after March 25, 2026 Anthropic service outage
All local cleanup attempts failed (cleared cookies, session storage, config, vm_bundles, full reinstall)