For an existing Office Home & Business 2021 for Mac one-time purchase that is already shown under Services & subscriptions, the supported recovery path is:
- Make sure the Mac is using the correct Office build
If Office was ever installed from the Mac App Store, that build does not use the licensing helper tool and can cause activation issues for perpetual licenses. Remove the current Office apps from Finder > Applications by moving Word, Excel, PowerPoint, and Outlook to Trash.
- Reinstall Office directly from Microsoft
Install the Microsoft-delivered Office for Mac package again, not the Mac App Store version. After installation completes, open an Office app.
- Remove saved license state again, then reactivate
Run the official license removal tool:
- Download the tool.
- Open the
.pkg from Downloads.
- If macOS shows an unidentified developer warning, use Control + click > Open.
- Select Continue, then Install.
- Enter the Mac local admin password if prompted.
- When finished, open an Office app and sign in with the same Microsoft account that owns the Office Home & Business 2021 for Mac license.
Important: this removes all Office license data from the Mac, so the correct account credentials must be ready before doing it.
- If prompted to choose a license, choose the one-time purchase
If the account has both Microsoft 365 and a perpetual license associated with it, Office can prompt for a license choice during activation. Select Office Home & Business 2021 for Mac.
- Restart the Mac immediately after successful activation
A documented Microsoft Q&A resolution for this exact behavior was:
- run the License Removal Tool
- launch Word and activate, selecting Office Home and Business 2021 Mac
- confirm About Word shows the Office 2021 license
- immediately quit Word and reboot the Mac
After reboot, the Office apps continued using the Office 2021 license.
- If activation still fails with helper-related behavior
Office for Mac perpetual licenses rely on the licensing helper tool. That helper is included in the Microsoft installer package and is not installed or used by the Mac App Store version. Updating Office through Microsoft AutoUpdate can also update the helper tool automatically.
If Word still shows No License Found after reinstalling from Microsoft, running the license removal tool, signing in with the licensed account, selecting the 2021 license if offered, and restarting the Mac, the next supported check is to verify the installation is the Microsoft installer build and not the Mac App Store build.