If you suddenly encounter Activation Error codes such as 0xC004E016, 0xC004F210, 0xC004F034, and 0xC004F00F on your Windows 10 computer, then they all point to the same issue – Invalid Product Key or Version mismatch. When you see any of the aforementioned error codes above, it indicates that you are either entering a wrong product key or you are using an incorrect ISO when installing it on your computer. In such cases, you may see either of the following error messages:
“You are running Windows 10 Pro, but you have a valid digital license for Windows 10 Home.”
Or:
“The specified product key is invalid or is unsupported by this version.”
If you got the error code 0xC004F00F then it means that you’ve entered a product key for the Enterprise edition of Windows to activate Windows 10 Pro or Windows 10 Home. It could be that you have a key from your work and you accidentally use it on your Home PC.
If you got the error codes 0xC004E016, 0xC004F210, then it means that you have entered a product key that is meant for a different edition or version of Windows. On the other hand, if you got the error code 0xC004F034 instead, then it means that you have entered an invalid product key or a product key for a different Windows version.
Whichever error codes you have, refer to the possible solutions given below to fix the Invalid Product Key or Version mismatch Activation Error in Windows 10.
The first thing you can do to resolve this Activation error is to run the Windows 10 Activation Troubleshooter. To do so, follow these steps:
There is an exception offered by Microsoft – if you are connected to a Microsoft account prior to the hardware change, then you can most certainly use the same license key to reactivate Windows 10 again. Microsoft calls this an “Exception path” which should be fixed easily by the Windows Activation Troubleshooter as pointed out earlier. However, if the Windows Activation Troubleshooter isn’t able to resolve the error you can try purchasing a new license. In such rate case, even if you do have a Microsoft account available on your Windows 10 computer, and if Windows was never activated, this solution will not work. And if you haven’t connected your Microsoft account with your Windows 10 computer prior to the major hardware change, then your only option left is to purchase a new license. For you to do that here are some steps you can follow.
Note: If you are an IT administrator, you need to keep in mind that there is a limit to the number of times you can reactivate Windows on your computer. Moreover, if you don’t see any option to reactivate the license, and it is a work computer, you need to contact your organization’s tech support.
Activating Windows 10 can also be done using your phone. Just note that you have to call Microsoft to do so.

ExpressFiles is a program developed by Express Solutions. A number of Anti-Virus programs have flagged this program as a Potentially Unwanted Application. In many instances, it is bundled with additional programs on installation.
The program claims it offers users easy to search for various currently popular search terms. During our testing, the software never displays any search results, no matter the search words. Upon installation and setup, it defines an auto-start registry entry which makes this program run on each Windows boot for all user logins. A scheduled task is added to Windows Task Scheduler in order to launch the program at various scheduled times. The program defines an exception rule in Windows Firewall, allowing it to connect to the internet without limitations and auto-update itself.
net stop wuauserv net stop bits
net start wuauserv net start bitsSince the folder has already been flushed, it will be populated afresh the instant your restart your computer and open Windows Update. Now try to update your computer again and see if the error is fixed or not.
“SYSTEM [DRIVER] USB AUDIO DEVICE An audio stream is currently in use [DRIVER] Legacy Kernel Caller.”Step 2: The next thing you have to do is remove all the external hardware connected to your computer. In this step, you have to disconnect external hardware from your computer. Based on reports from users who experienced the same issue, the “TV card” is the culprit so make sure you remove that one. Once you’ve removed it, open Command Prompt and run the “powercfg –requests” command again and you’ll see that the “Legacy Kernel Caller” will no longer be on the list. In addition, your computer will get into its regular sleep mode once the hardware is removed. Once you do that, the driver gets hung and won’t release the power request despite being used. Step 3: Try using the request override option The powercfg command also offers a request override option which allows users to disable the requests from applications and services to wake the computer from sleep mode. To run this command, simply open Command Prompt with admin privileges. After you open Command Prompt, type the following command and hit Enter to disable requests from applications and services that causes the computer to wake from sleep state.
Powercfg -requestsoverride Driver "Legacy Kernel Caller" SystemStep 4: Check the streaming and media applications You also have to check if your computer is running an audio or video service in the background. In such cases, your computer won’t be able to go to sleep mode if these services are running in the background. You might have noticed that when you play a video or audio, your computer never goes to sleep. And if you have put it to sleep in between watching the video, then it’s probably why your computer is waking up. Thus, you have to stop these services. Step 5: Check the devices that can wake your computer If you didn’t see the Legacy Kernel Caller in the result after you execute the ”powercfg –requests” command, then you can try to execute the following command instead.
powercfg –devicequery wake_armedAfter you enter this command, it will give you a list of all the devices that can wake your computer. So if there is anything other than the mouse, keyboard, touchpad, you have to check the power configuration of that device. To do that, go to the Device Manager and disable the device’s “Allow this device to wake the computer” option in its Properties Step 6: Check the Sleep Advanced Settings
Error Causes