You must use a valid product key to activate Windows – 0x800704cF

 

Windows Activation system keeps checking for validity of your key from time to time. Assuming you have a genuine key and all of a sudden you have received Windows Activation Error 0x800704cF, then this error means we didn’t find a valid Windows license for your computer. In this guide, we will share how to fix Windows Activation Error 0x800704cF.

You must use a valid product key to activate Windows, Windows Activation Error 0x800704cF.

You must use a valid product key to activate Windows – 0x800704cF

Windows Activation Error 0x800704cF

The first thing I will recommend you is to run the Windows 10 Activation Troubleshooter via Settings > Update & Security > Activation, and then select Troubleshoot. It should be able to resolve the issue automatically and activate your Windows.

In case this has failed, follow the steps as below:

  1. Make a note of your Product key on the notepad on the computer.
  2. Go to Settings > Update & security > Activation .
  3. Select Change product key, and then enter the 25-character product key.

Your product key should be in the confirmation email you received after buying Windows, included with the packaging that came with your Computer, or on the Certificate of Authenticity (COA) attached to the back or bottom of your Computer.

This will restart the activation process on your Windows 10 Computer. Once Microsoft validates the keys, it will activate your Windows. In case it says the key is not valid, you may have to buy a new one.

I have seen this error reported with a peculiar case. One of the forum users reported that his Windows kept getting activated and deactivated. If that’s the case only Microsoft Support team can help. Many a time, when a computer tries to activate itself a lot, the server blocks that key.

Lastly, try to remember if you did any major hardware change on your Windows 10 computer. If yes, this could be the reason why the Activation process is not able to find the key. Windows 10 OS Stores the key locally and is in relation with your hardware configuration. If something major changes, the combination becomes invalid. If this is the case, check out the solution which is the same as 0xC004F211

Original Article