When Windows 10 launched back in 2015 Microsoft made it a free upgrade for millions of users running Windows 7 and 8. The way this worked meant you didn’t get a new product key and this can cause a few issues if you ever need to reinstall Windows 10. 

If you’re having problems activating Windows 10, here are some reasons why that might be and how to go about fixing it.

Is Windows 10 activated?

You can check on the activation status in the Settings app. Click on the Start icon, then the cog to open Settings.

Now to go Update & Security, then Activation. Here’s what you should see when Windows is correctly activated:

How to fix Windows 10 Activation Problems

What you’ll also notice is various links and options to get help and attempt to solve activation issues.

Troubleshooting activation problems

The Activation section in the Settings app should give you enough information to work out why Windows can’t activate. It’s worth trying a different network connection if possible, so switch from Wi-Fi to Ethernet or vice versa to see if that helps.

Another check to make before trying any of the suggestions below is to update Windows 10 to the latest version. Do this by using the Windows Update option which you'll find in Settings > Update & security > Windows Update.

If Windows 10 was activated previously and is now telling you it is not activated, it’s likely because you changed some hardware, typically something major like the motherboard.

How to fix Windows 10 Activation Problems

Windows has to be reactivated in order to prevent you using the same key on multiple (or too many) PCs or laptops, and changing the motherboard and processor can make it look to Windows like it’s a totally different PC.

Annoyingly, if you upgraded from Windows 7 or 8 and then reinstalled Windows, this reactivation doesn’t happen automatically – or at least not in our experience. This may be because you never linked your Windows 10 product key with your Microsoft account, and you probably didn’t do that because you didn’t know you could.

In any case, there are a couple of things you can do. First is to click the Troubleshoot link on the Activation page in Settings. If it works, it’s the easiest fix possible, but it probably won’t.

If there’s an error code, you can type that into a search engine to get more details, but you’ll probably find that there’s nothing you can do yourself to fix the problem. There are a couple of exceptions. Some software – a firewall – might be preventing Windows communicating with the activation servers, your internet connection might be down or the servers themselves might be overloaded or temporarily unavailable. You’re trying to use a Product Key for a different version of Windows 10 than you’ve installed, in which case reinstall the correct version, such as Home or Pro – they use different Product Keys).

Another obvious step is to click on Change Product Key and enter your key, assuming you have one. If you don’t have one, perhaps because you upgraded from an older version of Windows, you’ll need to call on Microsoft tech support.

You can do this using the built-in Get Help app. Search for it by typing ‘Get Help’ in the search box next to the Windows icon on the desktop.

How to fix Windows 10 Activation Problems

Just follow the on-screen prompts to type a description “I can’t activate Windows” and then choose from the options available. These should include a live chat as well as a phone number to request a call-back.

The assistant will likely ask for your product key (which you don’t have) or the product key for the old version of Windows that you upgraded from. If you don’t have that, then unfortunately it’s game over, as Microsoft will not activate Windows 10 for you without some proof that you’re entitled to it.

Your only option at that point is to buy a product key. There are ways to buy it cheaper than Microsoft’s official price.