Fix ERROR_NDIS_ADAPTER_NOT_FOUND (0x80340006) network interface not ready

You're trying to connect to the internet, and bam — error 0x80340006. This usually hits right after Windows wakes from sleep, or when you plug in a USB Ethernet adapter that the system refuses to recognize. I've seen it on Dell Latitude laptops with Realtek PCIe GbE Family Controller, especially after Windows Update pushed a driver in the background. The exact trigger: Windows tries to talk to the NDIS (Network Driver Interface Specification) layer, but the adapter either isn't registered or is in a bad state.

What's actually broken here

The NDIS stack is what lets your OS talk to the network hardware. When Windows boots or resumes, it registers each network adapter with the NDIS service. If that registration fails — because the driver is corrupt, the device is disabled, or the power state got confused — you get this error. The adapter might still appear in Device Manager, but it's basically a ghost. Windows can't send or receive anything through it.

Don't waste time checking your router or cables first. The problem is on the PC, not the network.

Step-by-step fix

1. Open Device Manager. Press Win + X and select Device Manager. You should see a list of hardware categories.
2. Expand Network adapters. Look for your Ethernet adapter. It might say something like "Realtek PCIe GbE Family Controller" or "Intel(R) Ethernet Connection I219-V." If the adapter has a yellow triangle, that's a driver problem. If it's missing entirely, scroll to View > Show hidden devices.
3. Uninstall the driver. Right-click the adapter and select Uninstall device. Check the box that says Delete the driver software for this device if it appears. This removes the corrupt driver files.
4. Restart the PC. Don't skip this. Windows will re-detect the adapter and install the default driver. After the restart, check Device Manager — the adapter should be there without the yellow warning.
5. Reset the network stack. Open Command Prompt as administrator (right-click Start, select Windows Terminal (Admin) or Command Prompt (Admin)). Run these commands one at a time, pressing Enter after each:

   netsh winsock reset
   netsh int ip reset
   ipconfig /release
   ipconfig /renew
   ipconfig /flushdns

   After the last command, restart the PC again. This clears any corruption in the NDIS layer, renews your IP address, and flushes DNS cache.
6. Disable fast startup. This is the real fix for many users who see the error after waking from sleep. Go to Control Panel > Power Options > Choose what the power buttons do. Click Change settings that are currently unavailable. Uncheck Turn on fast startup. Click Save changes. Fast startup sometimes doesn't reinitialize network adapters properly on resume.
7. Power cycle the network adapter. Open Device Manager again. Find your adapter, right-click, select Disable device. Wait 10 seconds. Right-click again, select Enable device. This forces the NDIS stack to re-register the adapter.

If it still fails after these steps

Try these in order:

• Check the physical connection. Unplug the Ethernet cable and plug it back in. Try a different cable. If you're using a USB adapter, try a different USB port — preferably a USB 2.0 port if you're having issues with USB 3.0.
• Update the BIOS on your motherboard or laptop. I've seen outdated BIOS cause weird NDIS registration failures. Check your manufacturer's support site for the latest version.
• Run the built-in network troubleshooter. Go to Settings > System > Troubleshoot > Other troubleshooters > Network Adapter. Run it and let Windows attempt auto-fixes. It won't always work, but it's worth trying before you pull your hair out.
• Check for Windows updates. Sometimes Microsoft releases a patch that addresses NDIS stack bugs. Go to Settings > Windows Update > Check for updates. Install any pending updates and restart.

If you're still stuck after all this, the adapter might be physically failing. On a desktop, you can swap in a cheap PCIe Ethernet card. On a laptop, you're looking at a USB Ethernet adapter or a motherboard-level repair. But 9 times out of 10, the driver uninstall and fast startup toggle fixes it. Try that first.