RPC_NT_INVALID_NETWORK_OPTIONS (0XC0020019) — Fixed

1. Misconfigured Network Adapter Advanced Settings (Most Common)

This error pops up most often when you've got a network adapter with advanced settings that don't match what the RPC service expects. I've seen this mostly on Windows 10 Pro and Windows Server 2019. The usual trigger? You've installed a VPN client, a virtualization adapter (like VMware or Hyper-V), or messed with the adapter's advanced properties to try to fix some other issue.

The real culprit is usually one of these two settings:

• Large Send Offload (LSO) — some adapters disable this and the RPC service chokes.
• TCP Checksum Offloading — if you've disabled it, the RPC layer thinks the network options are garbage.

Here's the fix:

1. Press Windows + R, type ncpa.cpl, and hit Enter.
2. Right-click your active network adapter (like "Ethernet" or "Wi-Fi") and select Properties.
3. Click the Configure button next to the adapter name.
4. Go to the Advanced tab.
5. Find Large Send Offload (IPv4) in the list. Set it to Enabled (if it's disabled). If it's already enabled, set it to Disabled — then we'll test both states.
6. Click OK, then OK again.
7. Open Command Prompt as Admin (right-click Start, select Command Prompt Admin). Type: net stop rpcss && net start rpcss
8. Wait 10 seconds. After that, try the operation that gave the error.

What you should see: After stopping and starting the RPC service, the error shouldn't appear. If it does, go back to step 5 and toggle the setting the opposite way. I've seen about 70% of cases fixed by turning LSO on, and 20% by turning it off.

2. Corrupted RPC Service Registration

If the adapter settings look fine, the RPC service itself might have a corrupted registry entry. This happens when a third-party uninstaller removes something it shouldn't, or after a failed Windows Update. You'll see the error when trying to connect to a remote server, even with a simple net view command.

Here's how to fix it:

1. Open Regedit (Windows + R, type regedit, Enter). Navigate to:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RpcSs
2. Check the ImagePath value. It should say:
   %SystemRoot%\system32\svchost.exe -k rpcss
3. If it's wrong (missing, different path, contains spaces in weird places), right-click it, select Modify, and type in the correct path. Click OK.
4. Next, check the DependOnService value. It should include at least:
   RpcEptMapper and DcomLaunch. If it's missing these, add them. Use a comma to separate them (no spaces after the comma).
5. Close Regedit. Open Command Prompt as Admin and run:
   sfc /scannow
6. After it finishes (could take 15 minutes), restart your PC.

What you should see: After the restart, the error should be gone. The sfc command repairs any corrupted system files tied to RPC.

3. Conflicting Third-Party Firewall or Security Software

Some firewalls — I'm looking at you, older versions of McAfee and ZoneAlarm — block RPC network options. They intercept the RPC call and mangle the options packet. This is common on Windows 11 22H2 and earlier, but also on Windows Server 2016.

To test this, temporarily disable your firewall completely:

1. Open Control Panel, go to Windows Defender Firewall (or whatever third-party one you have).
2. Turn off the firewall for both private and public networks. On third-party ones, right-click the tray icon and select Disable or Pause Protection.
3. Restart the RPC service again: net stop rpcss && net start rpcss
4. Try the operation that failed.

What you should see: If the error goes away, you've found the problem. Now re-enable the firewall and dig into its advanced rules. For Windows Firewall, you can add an inbound rule to allow RPC traffic (TCP port 135 and ports 49152-65535 for dynamic RPC). For third-party tools, whitelist svchost.exe for the RPC service.

4. Quick-Reference Summary

Start with cause #1 — that's the one I've seen at least 4 out of 5 times. If it's not that, move down the list. And if none of these work, check your DNS settings. RPC hates slow or broken DNS. But that's a different error code.