BUG] Cowork Dispatch "Session couldn't be created" on Windows — regular Cowork works, fails on two machines

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?

Dispatch fails immediately with "Session couldn't be created" and Retry loops forever.
Environment: Windows 11, PowerSpec B748 (ASUS Prime Z690-P, i7-12700K), Claude Desktop latest, Pro plan. Also fails identically on a second machine (Lenovo laptop).
Troubleshooting done: enabled Intel VMX in BIOS (Task Manager confirms "Virtualization: Enabled"), enabled VirtualMachinePlatform and HypervisorPlatform via DISM + reboot, reinstalled the Cowork workspace VM, force quit/relaunched, disconnected/reconnected.
Key detail: regular Cowork sessions work perfectly on both machines (VM service runs, shell commands execute). Failure is isolated to Dispatch. Two different machines failing the same way suggests account-side or server-side, not hardware. Related: #43991, #45990, #46093

What Should Happen?

Dispatch should create a session.
For the dropdowns: Operating System = Windows, Is this a regression = "No, this never worked", anything else you're unsure of can be left default or "unknown."

Error Messages/Logs

Session couldn’t be created.

Steps to Reproduce

click dispatch

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.209

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_