Issue with Microsoft Office Home & Student 2021 One-Time Purchase License

No. A one-time Office 2021 license does not require a Microsoft 365 subscription to keep using the included apps.

This usually happens for one of these supported reasons:

1. The installed Office build does not match the license type.
   • On Mac, Office apps downloaded from the Mac App Store require a Microsoft 365 subscription for editing.
   • One-time licenses such as Office 2021 are only compatible with Office apps downloaded directly from Microsoft.
2. Office is using the wrong saved license or account.
   • If Office is picking up a different Microsoft 365, work, or school license, the perpetual Office 2021 license may not activate correctly.
3. The installed apps include products not covered by the license.
   • Office Home & Student 2021 includes Word, Excel, PowerPoint, and OneNote.
   • If the installed build expects apps outside that edition, activation problems can occur.
4. The local Office license data is stuck or corrupted.

Steps to resolve it without buying a subscription:

1. Check which Office version is installed.
   • In any Office app on Windows: File > Account.
   • On Mac: in the app menu bar, choose About.
   • Confirm whether the product shown is Office 2021 / Office LTSC 2021 or Microsoft 365.
2. Confirm the purchase is attached to the correct Microsoft account.
   • Sign in to Services & subscriptions and verify the Office Home & Student 2021 license appears there.
3. If using a Mac, make sure Office was not installed from the Mac App Store.
   • If it was, uninstall that copy and reinstall Office directly from Microsoft using the account that owns the one-time license.
   • Mac App Store versions are not compatible with one-time Office licenses and can show reduced functionality or subscription prompts.
4. If Office is signed in with the wrong account, sign out and sign back in with the Microsoft account used to redeem the Office 2021 purchase.
5. If the problem continues on Mac, use the Office license removal tool.
   • This removes saved Microsoft 365 for Mac license files so Office can reactivate cleanly.
   • Important: this removes all Office licenses stored on the Mac, so the correct account credentials must be available before doing it.
6. Reinstall Office from the Microsoft account that owns the license if the current installation still shows Microsoft 365 or remains unlicensed.

If the installed copy is from Microsoft and the correct account is being used, Office 2021 should continue to work as a perpetual license for the included apps. A Microsoft 365 subscription is only needed for the subscription-based Microsoft 365 apps, not to keep using a valid Office 2021 one-time purchase.

References:

• Office 2021 and Office LTSC for Windows and Mac FAQ | Microsoft Support
• Microsoft Office activation and the Mac App Store | Microsoft Support
• What Microsoft 365 business product or license do I have? | Microsoft Support
• How to remove Office license files on a Mac | Microsoft Support
• Office error "The products we found in your account can't be used to activate" | Microsoft Support
• Why am I unable to edit/save word documents and am being told I need a subscription, even though I own a license? - Microsoft Q&A
• Microsoft Office for Home and Business for Mac 2021 - Microsoft Q&A
• Microsoft Office stopped letting me edit. Requires Office 365 to edit - Microsoft Q&A
• Problem with office 365 - Microsoft Q&A