The message appears because the installed Office apps are not currently activated with a valid, non‑subscription license and are instead prompting to activate a Microsoft 365 subscription.
On Mac, this commonly happens when:
- The device previously used Microsoft 365 from work or school, and that subscription has ended or been deactivated.
- Old Microsoft 365 licensing data is still cached, so Word/Excel/PowerPoint think they must verify a Microsoft 365 subscription to allow editing.
To keep using Office apps without Microsoft 365, a standalone (perpetual) license such as Office Home & Student/Business 2021 or 2024 must be properly registered and the old Microsoft 365 license removed.
High‑level steps (based on the typical resolution):
- Remove the old Microsoft 365 license from the Mac so it is no longer tied to the former subscription.
- Make sure the new standalone Office license is correctly associated with the personal Microsoft account (not the old work/school account).
- Reinstall Office and sign in with the account that owns the standalone license so the apps activate against that license instead of Microsoft 365.
For Mac specifically, the key action is to remove the old license files, then reinstall and activate with the new, non‑subscription license. The process is summarized in the referenced Q&A as “Remove Office license,” which points to the official Mac license removal steps.
If there is only a Microsoft 365 Basic subscription on the account (and no standalone Office product or Microsoft 365 Personal/Family), desktop apps will not stay fully functional; that plan only allows using Office on the web and mobile, not full desktop editing.
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