Genuine versions of Windows are published by Microsoft, properly licensed, and supported by Microsoft or a trusted partner. You'll need a genuine version of Windows to access the optional updates and downloads that help you get the most from your PC.
Here are answers to some common questions about genuine Windows software.
Look for key features of genuine Windows software, such as the Certificate of Authenticity (COA), a proof of license label, and an edge-to-edge hologram. For more information, visit the Microsoft How to Tell website. Your safest option is always to buy Windows from Microsoft, or to buy a PC with Windows preinstalled directly from Microsoft or a store you know and trust.
If you're seeing these notifications, it's likely that your copy of Windows wasn't properly activated. Click the notification and follow the steps to repair Windows or buy a genuine version of Windows if you find out the software is counterfeit.
Windows will always be able to get critical security updates, even if your version isn't genuine. However, other updates and benefits are available exclusively for genuine Windows software.
Activation helps verify that your copy of Windows is used only on PCs that the Microsoft Software License Terms allow. It pairs your product key or digital entitlement with your hardware configuration. Usually, you only need to activate Windows once, unless you make a significant hardware change.
When your PC downloads updates, Windows checks to see if your product key or digital entitlement is valid. If it is, you're eligible to receive the latest updates from Microsoft. If it's not, your PC is running non-genuine Windows.
To learn how to activate Windows 10 or Windows 11, see Activate Windows.
You can't install Windows on more PCs than the Microsoft Software License Terms allow. Usually, a copy of Windows can only be installed on one PC. To learn more about licensing Windows on more than one PC, go to the Microsoft Volume Licensing website.
Yes. You'll still be able to get critical security updates. However, many updates are exclusively for customers with genuine versions of Windows. We strongly recommend that you get genuine Microsoft software immediately to keep you safer while using your PC.
Validation is an online process. It verifies that your copy of Windows is genuine and that critical Windows licensing files haven't been damaged, deleted, or removed. It takes only a few moments and lets Microsoft create a match between your PC's hardware profile and your 25-character product key or digital entitlement.
Your copy of Windows may need to be validated before you can get downloads and the updates which are reserved for PCs that are running genuine Windows. Windows might also prompt you to run genuine validation if activation isn't properly completed.
If your copy of Windows fails validation, you'll see a results page that tells you why it isn't genuine. You'll also see info about how to resolve the issue.
There are a few common scenarios in which Windows running on a PC might be discovered to be non-genuine during validation.
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Repairs. If your PC has been repaired, you might start to see messages on your desktop that Windows isn't genuine. If the repairs required Windows to be reinstalled, the technician may have activated Windows with a different key than you used when it was originally installed. You might not see the messages until you try to download something from the Microsoft Download Center that requires validation, and validation fails. To fix the issue, you can properly activate Windows by reentering your original product key. For other issues, you may need to buy a genuine version of Windows.
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1 License = 1 PC. Another common cause of Windows validation failure happens when you try to install Windows on more PCs than your license allows. For instance, if you purchased a copy of Windows and installed it on more than one PC, online validation might fail because the product key has already been used on another PC. The rule for most copies of Windows is that only one copy of Windows can be installed on one PC. To learn about licensing more than one PC, go to the Microsoft Volume Licensing website.
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Counterfeit software. Validation will also fail if you’ve inadvertently acquired and installed counterfeit Windows software. The Microsoft How to Tell website can help you identify counterfeit software and file a counterfeit software report if needed. Validation failure is common for versions of Windows that were purchased from an online auction site, or if Windows was on a used PC that you purchased. Remember to ask the seller for the Certificate of Authenticity and the original Windows disc, if there was one.
To file a counterfeit report, go to the Microsoft How to Tell website.
You can file an online report if you inadvertently bought or received counterfeit software, or have information about a person, business, or online site that might be selling counterfeit software. The report you submit will be treated as confidential. Microsoft devotes substantial time and energy to fighting software counterfeiting, and you can be assured that we will take appropriate action in response to your report.
If you got an error when you were activating Windows, you can find what it means. For details, go to Get help with activation errors.
You’ll need a product key when you install Windows. To learn more, go to Find a product key.
