Fix 0xC00000C3 STATUS_INVALID_NETWORK_RESPONSE

Windows returns this when a network driver hands back a malformed packet buffer. It's almost always a NIC driver or offload feature, not the network itself.

Quick answer

STATUS_INVALID_NETWORK_RESPONSE (0xC00000C3) means the Windows network stack received a response from a driver or remote endpoint that violates the expected protocol contract — usually a NIC driver returning a corrupt packet descriptor, not the router. Replace or roll back the adapter driver and disable offload features.

What's actually happening here

This isn't a generic "no internet" error. It sits at the NDIS layer — the boundary between the Windows TCP/IP stack and your network adapter's miniport driver. When the stack sends a request down to the driver and the driver hands back data that doesn't match the expected structure (wrong buffer length, invalid descriptor flag, missing completion status), the kernel raises STATUS_INVALID_NETWORK_RESPONSE.

In practice, I've seen this fire in three scenarios. First: a driver update pushed by Windows Update that shipped a buggy miniport for a Realtek RTL8168 or Intel I219-V adapter. Second: a VPN client (Cisco AnyConnect, older SonicWall, sometimes NordVPN's TAP driver) installing a filter driver that mangles the response path. Third: a TCP offload feature — especially Large Send Offload (LSO) or Receive Side Scaling (RSS) — that the driver claims to support but handles incorrectly under load.

The reason the router gets blamed is that users see this during a network stall, so they reboot the router. That doesn't help. The router isn't producing malformed NDIS descriptors; your own machine is.

If the error appears in Event Viewer under System with source NDIS or as a 0xC00000C3 bugcheck code alongside ndis.sys, it's local. If it's an application-level error from WinHTTP, the cause could be a proxy or middlebox.

Fix 1: Roll back or clean-install the adapter driver

Hit Win+R, type devmgmt.msc, expand Network adapters.
Right-click your physical NIC — Intel, Realtek, Killer, whatever's there — and pick Properties.
Go to the Driver tab. Note the driver version and date.
If the date is within the last 60 days, click Roll Back Driver. Windows will restore the previous version.
If rollback is greyed out, uninstall the device, tick Delete the driver software for this device, reboot, and let Windows install the inbox driver.

The inbox driver Microsoft ships is boring and slow but it's also been tested against the NDIS contract. Vendor drivers chase benchmarks and add features that break edge cases.

Fix 2: Disable offload features

This is the fix that resolves 0xC00000C3 for most people once the driver is stable. Offloads move packet processing off the CPU and onto the NIC's firmware. When the firmware has a bug, it produces descriptors the stack rejects.

In Device Manager, open the NIC properties, go to Advanced.
Set these to Disabled one at a time, testing after each: Large Send Offload V2 (IPv4), Large Send Offload V2 (IPv6), TCP Checksum Offload (IPv4/IPv6), UDP Checksum Offload (IPv4/IPv6), Receive Side Scaling, Interrupt Moderation.
If you want to script it across machines, use PowerShell as admin:

Get-NetAdapterAdvancedProperty -Name "Ethernet" | Where-Object {$_.DisplayName -match 'Offload|RSS'} | Set-NetAdapterAdvancedProperty -RegistryValue 0

You'll lose a few percent throughput. That's the trade. Stability beats a marginal CPU win on a gigabit link.

Fix 3: Reset the network stack

If the driver is clean and offloads are off but the error persists, the Winsock catalog or TCP/IP stack may have been corrupted — usually by an uninstalled VPN client that left filter drivers behind.

netsh winsock reset
netsh int ip reset
netsh int ipv4 reset
netsh int ipv6 reset
ipconfig /flushdns

Reboot after. Then check Get-NetAdapterBinding for any leftover filter drivers from vendors you no longer use. Unbind them with Disable-NetAdapterBinding -Name "Ethernet" -ComponentID vendor_filter_id.

Alternative fixes if the main path fails

Second NIC test: Plug in a cheap USB Ethernet adapter. If the error vanishes, your onboard NIC or its driver is the culprit. On Intel I225-V revisions before B3, this was a known silicon bug — RMA the board.
Safe Mode with Networking: If 0xC00000C3 doesn't appear in Safe Mode, a third-party filter driver is loading at boot. Check msconfig for services with 'NDIS', 'LSP', or vendor names.
Restore point: If the error started right after a Windows Update (22H2 to 23H2 jumps have triggered this on a few Realtek chipsets), roll back the cumulative update.
Registry clean-up: Stale entries under HKLM\SYSTEM\CurrentControlSet\Control\Class\{4d36e972-e325-11ce-bfc1-08002be10318} for NICs that no longer exist can confuse enumeration. Back up before deleting anything.

Prevention

Stop letting Windows Update silently push NIC driver updates. The real fix is to set a Group Policy or registry flag to exclude driver updates from the update stream:

HKLM\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate
DWORD: ExcludeWUDriversInQualityUpdate = 1

Then manage NIC drivers manually — grab them from Intel, Realtek, or your OEM's support page, and pin to versions the community has vetted. Driver updates are the single biggest source of 0xC00000C3 regressions, and the vendor's "latest" is often less stable than the one three revisions back. Test in a VM before you push anything to a production fleet.