Cowork connectin API bug

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 VM boots successfully, gets network connectivity (confirmed by successful SDK download), but consistently fails to reach the Claude API. Every attempt follows this exact pattern:

VM starts → Network status: CONNECTED
SDK installs successfully (proving VM has internet)
OAuth token approved with MITM proxy
API reachability: PROBABLY_UNREACHABLE (within seconds)
API reachability: UNREACHABLE (20 seconds later)

Regular Chat mode works perfectly. Only Cowork is affected.
Three Distinct Bugs Found
Bug 1: MITM proxy cannot route to api.anthropic.com
The VM has general internet access (SDK downloads work) but the authentication proxy fails to reach the API. The NAT rule had to be manually created (New-NetNat) as it was missing — but even with correct NAT configuration (172.16.0.0/24), API remains unreachable.
Bug 2: macOS diagnostics running on Windows
Every failure triggers === Comprehensive macOS Diagnostics === attempting:

/sbin/ifconfig (macOS only)
/usr/sbin/scutil (macOS only)
/usr/sbin/kextstat (macOS only)
/usr/bin/pgrep (macOS path)
/usr/bin/log (macOS only)

All fail with ENOENT. The diagnostic code was not ported to Windows.
Bug 3: HcnCreateEndpoint intermittent failure
On some boot attempts: failed to create network endpoint: HcnCreateEndpoint failed: hr=0x80070490, error={"Success":false,"Error":"Element not found.","ErrorCode":2147943568}
Troubleshooting Already Performed

Removed conflicting "WiFi for Sandbox" external VM switch
Disabled ZeroTier virtual adapter and service
Disabled Windows Firewall (Private profile)
Removed all HNS networks and let Cowork recreate
Manually created NAT rule (New-NetNat -Name "CoworkNAT" -InternalIPInterfaceAddressPrefix "172.16.0.0/24")
Deleted vm_bundles and claude-code-vm directories for clean rebuild (multiple times)
Restarted CoworkVMService and vmcompute services
Full app reinstall from claude.com/download
Windows Defender Network Protection is OFF (EnableNetworkProtection: 0)

Nothing resolves the API unreachable issue.

What Should Happen?

Cowork should connect to the Claude API successfully, the same way regular Chat mode does.

Error Messages/Logs

17:32:04 [info] [VM] Network status: CONNECTED
17:32:07 [info] [VM:steps] sdk_install completed (3354ms)
17:32:07 [info] [VM:start] Startup complete, total time: 14674ms
17:32:09 [info] [Spawn:vm] OAuth token approved with MITM proxy
17:32:09 [info] [VM] API reachability: PROBABLY_UNREACHABLE
17:32:32 [info] [VM] API reachability: UNREACHABLE
17:32:32 [warn] [VM:network] API is unreachable

17:14:59 [error] [VM:start] VM boot failed: failed to create network endpoint: 
HcnCreateEndpoint failed: hr=0x80070490, error={"Success":false,"Error":"Element not found.","ErrorCode":2147943568}
17:14:59 [info] [networkDiagnostics] === Comprehensive macOS Diagnostics ===
17:14:59 [error] Failed to spawn /sbin/ifconfig: ENOENT

17:14:59 [error] [VM:start] VM boot failed: failed to create network endpoint: 
HcnCreateEndpoint failed: hr=0x80070490, error={"Success":false,"Error":"Element not found.","ErrorCode":2147943568}
17:14:59 [info] [networkDiagnostics] === Comprehensive macOS Diagnostics ===
17:14:59 [error] Failed to spawn /sbin/ifconfig: ENOENT

Steps to Reproduce

1. Install Claude Desktop v1.1.3541.0 on Windows 11 Pro 25H2 (Build 26200.7840)
2. Log in with Max plan subscription
3. Switch to the Cowork tab
4. Select a folder and start a task
5. Observe: "Sorry, it's taking a while to connect to the Claude API..."
6. After ~30 seconds: "Taking longer than expected to reach the Claude API. Still trying..."
7. Eventually fails — API never connects
8. Check cowork_vm_node.log: VM boots, network CONNECTED, SDK installs, then API reachability: UNREACHABLE

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude 1.1.3541 (1e65e4) 2026-02-18T19:23:37.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_