How to Fix Windows 10 Activation Error 0xC004F078?

If you cannot activate your Windows 10 PC and get a Windows Activation Error 0xC004F078 on your computer, this post will help you fix it. This error generally occurs if the KMS (Key Management Service) is not reachable by the client computer. However, sometimes it also happens if the key used in the SLSetAuthenticationData function call is inaccurate.

Usually, this error appears in those devices that are upgraded from Windows 7 or Windows 8.1.
You may find any of the following error messages. It depends upon where you face it:

Windows is unable to reach your company’s activation service. Please connect to your corporate network. If you are connected and continue to see the error, contact your system administrator. You can also click on the error detail to find the exact error. Error code: 0xC004F074.
Activating Windows(R),(Key hash)…Error: 0xC004F074 This Software Licensing Service reported that the PC could not be started. So, No Key Management Service (KMS) could be contacted. Please see the App Event Log for additional information.
Error 0xC004F078, SL_E_AUTHN_MISMATCHED_KEY, The Software Licensing Service reported that the key is mismatched.

Windows 10 Activation Error Code 0xC004F078

Here is how to fix Windows 10 Activation error code 0xC004F078:

1. Use the Activation Troubleshooter

To fix this error, you first need to run the Windows 10 Activation Troubleshooter to check for the possible reasons causing this issue.

Open Windows Settings using Win + I keyboard shortcut.
On the next page, go to Update & Security > Activation.
Go to the right pane and click the Troubleshoot option.

Note: If you don’t see the troubleshoot option, then make sure to activate the OS. Also, you must sign in to Windows 10 as an Administrator to run the activation troubleshooter.

Once it completes the troubleshooting process, it will inform you so.
Follow the on-screen instructions to solve the respective activation issue.
Restart your system and try again for Windows Activation.

2. Use the correct key for your type of Windows copy

If the above method doesn’t work, you need to check whether OEM or Retail, Volume, and other details explore the issue to 0xC004F078. Plus, confirm that you are using the correct and valid product keys for your device.

3. Try to reinstall the key

The next solution requires you to Fix 0xC004F078 is reinstall the key using the elevated command prompt and check if it helps anymore. The steps are as follows:

Run the Command Prompt with Admin right.
In this elevated command prompt window, type the following commands:

slmgr.vbs /upk

Then type the following command and hit enter to install the KMS Product Key:

slmgr.VBS /ipk <The KMS Product Key>

Note: In the above command, replace <The KMS Product Key> with the Product key.

Running the above command will show you a notification that verifies if the operation was successful or not.
If you want to activate it online, type the following command:

slmgr.vbs /ato