Microsoft regularly releases free product keys for the various editions of Windows. Also known as generic product keys or default keys, it is not immediately apparent what they are for or why you should use them.

Will they give you a free copy of Windows? Are they available to use on any machine? And why does Microsoft make them available for free? Let's take a closer look.

What Are Windows 10 Generic Product Keys?

Generic product keys allow users to install any version of Windows on their machines. Each version of Windows has its own key.

To find the latest KMS generic keys (aka, default keys) for all editions of Windows 10, it is wise to check Microsoft's official list. They are prone to change from time to time. You can find the full list of generic Windows 10 keys on Microsoft's website.

Windows Server, Windows 10, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Server 2008 R2, Windows Vista, and Windows Server 2008 also have default KMS keys available.

Remember, all the keys listed by Microsoft require you to have configured a KMS host before they will work. Check out Microsoft's guide to deploying a KMS activation if you need further guidance.

You can also check out our guide on how to get Windows 10 for free.

Yes, there is nothing wrong with using a generic product key to install Windows on your computer. However, doing so comes with some significant restrictions.

Most notably, a generic key gives no usage rights. Instead, they are only designed to help you install Windows. Within 30 to 90 days (depending on the key), the generic key will expire, and you will need to add a full retail key.

In theory, Microsoft will never let you activate Windows using a generic key. If you try and activate Windows using a generic product key, you will see the following message on-screen:

We can't activate Windows on this device because you don't have a valid digital licence or product key. If you think you do have a valid licence or key, see Troubleshoot below. (0x803f7001)

Even if you somehow manage to bypass Microsoft's controls (and yes, there are ways of doing that), you will be in breach of the End-User License Agreement (EULA) and could be liable for prosecution.

Why Use Generic Product Keys on Windows 10?

It is perhaps best to think of generic product keys in the same way as you would think of a free trial for a piece of software. Yes, you get access to all the features and can put the app through its paces, but you know you'll need to spend some money at some point to retain access.

They are ideal for people who are building systems or who want to run Windows in a virtual environment.

How to Upgrade a Generic Product Key

windows key activation

If you used a generic product key to install Windows, you can easily replace it with a full retail version and thus obtain a legal copy of Windows without needing to delete and reinstall your operating system.

Note: Before following these steps, you first need to purchase a retail version of a Windows product key. You can buy them directly from the Microsoft online store. Some third-party sellers may also have legitimate keys available, but we cannot guarantee they will work.

We've explained why Windows activation keys might not work in an article elsewhere on the site.

When you are ready, open the Settings app and go to Update and security > Activation > Upgrade your edition of Windows > Change product key.

A new box will pop up on the screen, and you will be prompted to enter the retail key that you just bought.

If your key is legal, the activation process will begin. The process could take anything from a few seconds to several hours, depending on how busy Microsoft's servers are.