My 2021 license no longer works

Remove the current Office installation, then reinstall Office Home & Student 2021 from the Microsoft account to which your retail key was redeemed; you do not need to purchase or activate Microsoft 365.

Reinstall your Office 2021 license

1. Confirm that Office 2021 is attached to your account
   • Open the Microsoft account Services & subscriptions page.
   • Sign in with the Microsoft account used when redeeming the retail product key.
   • Confirm that Office Home & Student 2021 appears.
   A redeemed key is replaced by the associated Microsoft-account entitlement for subsequent installation and activation; entering the key again is normally unnecessary.^1^
2. Completely remove the incompatible Office installation
   • On Windows 10 or 11, use Microsoft’s Office uninstall troubleshooter on the same computer.
   • Follow its prompts and restart Windows when requested.
   • This removes the Office applications, not your Word documents or other files.^2^
   Alternatively, open Control Panel → Programs → Programs and Features, select the Office/Microsoft 365 installation, and choose Uninstall. If more than one Office installation is listed, remove the unwanted copies because multiple installations can cause activation conflicts.^3^
3. Download Office 2021 from your account
   • Return to the Microsoft account dashboard.
   • Select Office apps.
   • Find Office Home & Student 2021, then select Install.
   • Open the downloaded setup file, approve the Windows prompt, and wait for “You’re all set! Office is installed now.”^4^
   Do not use a general Microsoft 365 download page or install Word separately from the Store unless your account’s Office 2021 entry specifically directs you there.
4. Activate the perpetual license
   • Open Word.
   • Accept the license terms.
   • If prompted, sign in with the same Microsoft account that shows Office Home & Student 2021.
   • Open File → Account and check that the product information identifies the Office 2021 license rather than requesting Microsoft 365 activation.

What “perpetual” means now

Office Home & Student 2021 was a one-time purchase, not a free product or Microsoft 365 subscription. Your purchase did not become a Microsoft 365 subscription. However, support for Office 2021 ended on October 13, 2026. Microsoft says its apps may continue functioning, but they no longer receive technical support, software updates, bug fixes, or security fixes.^5^

Continuing to use it therefore carries security and compatibility risks, even if updates are unimportant to you.

Check your Windows version

If “Previous Windows versions” means Windows 7, Windows 8, or Windows 8.1, Office 2021 is not supported on those systems. Office 2021 is listed for Windows 10 with lifecycle-related exceptions and for Windows 11.^6^

If the account page does not show Office Home & Student 2021, the missing information needed to proceed is the Microsoft account originally used to redeem the retailer’s key. The full redeemed key is not displayed in Office or online; that associated account is what is used for reinstalling and activating Office 2021.^7^

References

1. Where to enter your Office product key | Microsoft Support
2. [Microsoft Store](https://support.microsoft.com/office/lifecycle/officeinstall/uninstall-microsoft-365-or-office-from-a-pc)
3. Unlicensed Product and activation errors in Office | Microsoft Support
4. [Office for Mac 2021](https://support.microsoft.com/office/lifecycle/officeinstall/download-and-install-or-reinstall-office-2021-office-2019-or-office-2016)
5. End of support for Office 2021 | Microsoft Support
6. [Other Office versions](https://support.microsoft.com/office/lifecycle/officeinstall/what-windows-end-of-support-means-for-office-and-microsoft-365#office-home-&-business,-office-home-&-student,-and-other-versions-of-office)
7. Using product keys with Microsoft 365 | Microsoft Support