Claude Desktop CoWork VM fails to start after update to v1.1.5368 — smol-bin.vhdx never downloaded

Summary

After updating Claude Desktop to v1.1.5368 on Windows, the CoWork workspace fails to start with:

"VM service not running. The service failed to start."

The issue persists after clearing cache, reinstalling the workspace, and restarting. This was working correctly on the previous version.

Root Cause (diagnosed from logs)

The HCS (Host Compute Service) VM config in v1.1.5368 now requires three virtual disk files:

1. rootfs.vhdx — downloaded correctly
2. smol-bin.vhdx — never downloaded or created
3. sessiondata.vhdx — never downloaded or created

The download process only fetches rootfs.vhdx, vmlinuz, and initrd. smol-bin.vhdx is referenced in the HCS config but is never provisioned, causing the VM to fail at construction.

Exact Error (from cowork-service.log)

[HCS] HcsWaitForOperationResult returned: hr=0x800707de
[HCS] Result JSON: {"Error":-2147022882,"ErrorMessage":"","Attribution":[{"OperationFailure":{"Detail":"Construct"}}]}

HCS Config (from log) — shows smol-bin.vhdx as required

"Scsi": {
  "Primary SCSI Controller": {
    "Attachments": {
      "0": { "Path": "...\\claudevm.bundle\\rootfs.vhdx", "Type": "VirtualDisk" },
      "1": { "Path": "...\\claudevm.bundle\\smol-bin.vhdx", "ReadOnly": true, "Type": "VirtualDisk" },
      "2": { "Path": "...\\claudevm.bundle\\sessiondata.vhdx", "Type": "VirtualDisk" }
    }
  }
}

Bundle download log (from cowork_vm_node.log) — only 3 files downloaded

rootfs.vhdx not found, downloading... ✓
vmlinuz not found, downloading... ✓
initrd not found, downloading... ✓
All files ready  ← but smol-bin.vhdx and sessiondata.vhdx are never downloaded

Environment

• Claude Desktop version: 1.1.5368 (commit: d12d0218c6c7bc46d52919117bd57508c591a8ad)
• Platform: Windows 11 (10.0.26200), x64
• CPU: 11th Gen Intel Core i7-1165G7
• RAM: 48 GB
• Hyper-V / HCS: Running (vmcompute service status: Running)
• WSL2: Running (confirming virtualization is functional)
• Bundle version attempted: fb30784dadb34104626c8cf6d8f90dd47cd393cc

Steps to Reproduce

1. Update Claude Desktop to v1.1.5368
2. Open CoWork workspace
3. Error appears immediately
4. Reinstalling workspace from within the app re-downloads only rootfs.vhdx/vmlinuz/initrd — smol-bin.vhdx is still missing
5. Error persists indefinitely

Expected Behavior

Either:

• smol-bin.vhdx should be included in the bundle download manifest, OR
• The CoWork service should generate/create it on first run

Impact

CoWork is completely non-functional after this update. Reinstall does not resolve it.