[BUG] Cowork broken after auto-update to 1.1.5749 — yukonSilver marked unsupported (was working on previous version)

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 stopped working after Claude Desktop auto-updated to v1.1.5749 on March 9, 2026. It was working fine on the previous version. The app now classifies yukonSilver as unsupported and never attempts to start the VM. The vm_bundles folder does not exist — the VM never downloads or starts.

What Should Happen?

Cowork should start normally as it did before the 1.1.5749 update. yukonSilver should be recognized as supported on this system.

Error Messages/Logs

HCS operation failed: failed to create compute system: HcsWaitForOperationResult failed with HRESULT 0x800707de: {"Error":-2147022882,"ErrorMessage":"","Attribution":[{"OperationFailure":{"Detail":"Construct"}}]}

cowork_vm_node.log:
2026-03-10 07:04:30 [info] [cleanupVMBundleIfUnsupported] yukonSilver not supported (status=unsupported), checking for stale bundle...

Note: vm_bundles folder does not exist at all — VM never attempts to download or start.

Steps to Reproduce

1. Cowork was working fine on the previous version
2. 2. Claude Desktop auto-updated to 1.1.5749 overnight on March 9, 2026 (pushed as a DST hotfix)
3. 3. Open Claude Desktop and navigate to Cowork tab
4. 4. Error appears immediately
5. 5. Restart and full reinstall do not fix it
6. 6. vm_bundles directory never gets created — VM is blocked before any download attemptPrevious version before 1.1.5749 (auto-updated March 9, 2026)

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Unknown — version before 1.1.5749 (auto-updated March 9, 2026)

Claude Code Version

Claude Desktop 1.1.5749 (Microsoft Store / MSIX)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

System Info:

• OS: Windows 11 Business, Version 25H2, OS Build 26200.7840
• - CPU: 12th Gen Intel Core i9-12900H
• - - Install type: Microsoft Store (MSIX)

Related issues: #25136, #30997, #32579
This appears to be a regression introduced by the 1.1.5749 DST hotfix released March 9, 2026. Cowork was fully functional the day before.