Office 2021 for Mac

Check the installed Office version and displayed license first, then reactivate Word or Excel with the Microsoft account linked to the Office 2021 purchase.

1. Identify the version and license being used

1. Open Word or Excel.
2. On the macOS menu bar, select Word/Excel > About Word/Excel.
3. Note:
   • The application version, particularly whether it is 16.114.1.
   • Whether the product shows Office 2021, Microsoft 365, or Unlicensed.
   • The exact activation error.

This determines whether Office has selected the wrong account/license or is affected by a version-specific issue.

2. Verify and reactivate the Office 2021 license

1. Sign in to the Microsoft account dashboard and look for Office 2021, Office Home & Student 2021, or Office Home & Business 2021 under the account’s products.
2. If it is absent, check any other personal Microsoft accounts that may have been used when the product key was first redeemed. Redeeming a key associates Office permanently with that account.
3. In Word or Excel, sign out of any work, school, or Microsoft 365 account.
4. Quit all Office applications.
5. Reopen Word, select Sign in, and use the account displaying the Office 2021 purchase. If no prompt appears, select File > New from Template > Sign in. Office checks the account’s license during activation.^1^
6. Restart Word and test Save.

3. Apply the matching version-specific action

If About Word/Excel shows version 16.114.1 and the message specifically says that the Office 2021 license is unsupported in this version, uninstall that build and install the officially sourced 16.114 package described in the matching Office 2021 case. After installation, open Help > Check for Updates and temporarily clear Automatically keep Microsoft apps up to date to prevent 16.114.1 from reinstalling.^2^

This is a conditional workaround, not the appropriate fix for other activation errors. Disabling automatic updates also withholds security and reliability updates, so re-enable them once Microsoft releases a compatible corrected build.

If the message is “License Not Found” or “Unknown Error 0x0,” and the installed version is not the problematic build above:

1. Confirm the Mac is running macOS 12 or later.
2. Quit all Office applications.
3. Open Finder > Applications > Microsoft AutoUpdate. If it is not listed there, check: /Library/Application Support/Microsoft/MAU2.0/
4. Install the available Office updates and retest.
5. If Office came from the Mac App Store instead, open App Store > Updates and update Word, Excel, PowerPoint, and the other Office apps there.^3^

4. Reset stale licensing data if activation still fails

This removes all Office licenses stored on the Mac, so first verify that the Office 2021 purchase appears under the correct Microsoft account and that its password works.

1. Quit every Office application.
2. Download and run Microsoft’s Office for Mac License Removal Tool.
3. Select Continue, complete the wizard, and enter the Mac administrator password if requested.
4. Open Word and sign in with the account associated with Office 2021.
5. If offered several licenses, select the one-time-purchase Office 2021 license.
6. Restart the Mac after activation succeeds.^4^

5. Conditional licensing-helper and reinstall checks

If activation reports a licensing helper, background-service, or permissions error:

1. Open System Settings > General > Login Items & Extensions.
2. Under Allow in the Background, enable Microsoft Corporation and Microsoft Office Licensing.
3. Restart the Mac and reactivate Office.^5^

If that does not apply or does not resolve it, uninstall Office for Mac and reinstall it from the Microsoft account that displays the Office 2021 purchase. From the account dashboard, select Office apps, locate Office 2021, and select Install; after installation, open Word and complete activation.^6^

If Office 2021 is missing from every Microsoft account, contact Microsoft Support and provide the purchase receipt and product-key documentation. If the license was supplied by the iMac retailer and was never associated with a Microsoft account, also ask that retailer to confirm what license was sold and how it was redeemed.

References

1. Activate Office for Mac
2. Office 2021 Home & Student license suddenly stopped working on Mac - Microsoft Q&A
3. Unknown Error 0x0 or License not found error in Microsoft 365 or Office running on macOS | Microsoft Support
4. How to remove Office license files on a Mac | Microsoft Support
5. Office 2021 license does not work and ist not anymore in the portal listed - Microsoft Q&A
6. [Office for Mac 2021](https://support.microsoft.com/office/lifecycle/officeinstall/download-and-install-or-reinstall-office-2021-office-2019-or-office-2016)