Word Activation Error on Mac

Yan Staley 0 Reputation points
2026-09-08T23:00:05.2333333+00:00

I'm using Microsoft 365 Family through a family member's shared subscription. The subscription shows as "Shared," and I have accepted the family invitation. My Mac was upgraded from Big Sur 11.7.10 to Monterey 12.7.6 because Office said the operating system needed to be updated. Word desktop still won't activate and shows "Unknown Error 0x0." Microsoft AutoUpdate also gives an update error for all Office apps. Word on the web works normally. How do I solve this issue? Thank you very much for your time and help!

Microsoft 365 and Office | Install, redeem, activate | Other | MacOS
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  1. EmilyS726 266.9K Reputation points Independent Advisor
    2026-09-08T23:37:12.14+00:00

    For macOS Monterey 12, Microsoft 365 is no longer supported for current updates.

    The August 2024 release, version 16.88, was the final Office build supporting Monterey. An existing installation may continue to work, but it will not receive security updates, fixes, or new features. Current Microsoft 365 and Office 2024 installations require macOS Sonoma 14 or later.

    You will need to uninstall it. And install the downgraded version (16.88) here: https://officecdn.microsoft.com/pr/C1297A47-86C4-4C1F-97FA-950631F94777/MacAutoupdate/Microsoft_365_and_Office_16.88.24081116_Installer.pkg?apid=ets

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  2. AI answer

    2026-09-08T23:00:23.1+00:00

    For this Mac scenario, the most relevant fixes are to clear the Office activation credentials, remove old license files, and then reactivate with the shared Microsoft 365 account.

    1. Confirm the shared account is the one being used in Word.
      • In Word, sign out.
      • Sign back in with the Microsoft account that accepted the Microsoft 365 Family sharing invitation.
      • If needed, choose Sign in with another account.
    2. Reset the stored Office credentials in macOS Keychain.
      • Open Spotlight.
      • Search for and open Keychain or Keychain Access.
      • Search for Office.
      • Delete the Office data license file.
      • If Word keeps prompting for activation after that, also delete these items if present:
        • Microsoft Office Identities Cache 3
        • Microsoft Office Identities Settings 3
        • Microsoft Office Ticket Cache
      • Restart the Mac.
    3. Run the Microsoft license removal tool.
      • Use the official license removal tool for Mac.
      • Then restart the Mac again.
      • This is especially useful if Office is activated with the wrong license or old license data is stuck.
    4. Open Word and reactivate.
      • Start Word after the restart.
      • Sign in again with the shared Microsoft 365 Family account.
      • If activation succeeds, the app should stop showing Activate Microsoft 365 to create and edit.
    5. If Office apps keep asking to sign in or show authentication problems, check the app location.
      • Office for Mac can repeatedly ask to sign in or show Authentication Expired if the apps were moved from the default /Applications folder.
      • If that applies, follow the keychain reset guidance for repeated keychain access prompts.
    6. If Microsoft AutoUpdate is failing for all Office apps, reinstall Office from the Microsoft 365 apps page.
      • Uninstall and reinstall Office for Mac, then activate again after reinstall.
      • If the installer download gets stuck or fails, use Safari, clear website data, and download again from Microsoft 365 apps.
    7. If the Mac was recently updated from Big Sur and the desktop apps still fail while Word on the web works, a full license reset is the strongest supported path:
      • Remove Office license files.
      • Restart the Mac.
      • Reinstall Office.
      • Sign in again with the shared subscription account.

    Important:

    • Initial activation requires internet access.
    • Changes in Keychain Access may require local admin privileges.
    • Reinstalling Office is not destructive to documents, but deleting the wrong Keychain items can affect saved sign-in state for Office.
    AI-generated content may be incorrect. Read our transparency notes for more information.

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