Windows shows 'Windows is not activated' or an activation error

Symptoms

• Watermark appears in the bottom-right corner of the desktop
• Settings > Activation shows an error or 'Windows isn't activated'
• May follow a hardware change, reinstall, or a long time without internet access
• Personalization options may be restricted while unactivated

Likely causes

• CommonRecent significant hardware change (especially the motherboard)Windows activation is often tied to hardware, and major changes can require reactivation.
• CommonRecent clean install or reinstall of WindowsA fresh install needs to reconnect with Microsoft's activation servers, which can occasionally fail silently.
• PossibleNo internet connection at the time Windows tried to verify activationActivation typically needs to check in with Microsoft's servers periodically.
• PossibleLicense transferred or used on too many devicesCertain license types have restrictions on the number of active installations.
• Less commonProduct key genuinely invalid or already in use elsewhereRare but possible with certain non-retail or improperly obtained keys.

What to do

1. Confirm you have an active internet connection, then go to Settings > System > Activation and click 'Troubleshoot' if that option appears.
2. If you recently changed hardware, especially the motherboard, and you're signed in with the Microsoft account originally used to activate Windows, the troubleshooter can often relink the license to the new hardware.
3. Check that you're signed into the same Microsoft account that was used when Windows was originally activated, if applicable.
4. If you have a physical product key or a digital receipt from a purchase, go to Settings > System > Activation > Change product key, and re-enter it.
5. Restart the computer and check activation status again, since it can sometimes resolve after a fresh connection attempt.
6. If the PC came pre-installed with Windows (OEM license), check that no major hardware beyond upgrades (like just adding RAM or a drive) has changed, since OEM licenses are more hardware-tied.
7. If activation still fails and you're confident your license is legitimate, contact Microsoft support directly, since they can look into account-specific licensing issues.

When to call a pro

If troubleshooting through Settings doesn't restore activation and you believe your license is valid, Microsoft support or a technician can help resolve account or hardware-linking issues.

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