Microsoft Word for Mac shows “Unknown Error 0x0” even after updating to the latest version

Palash Samadhiya 0 Reputation points
2026-10-01T11:51:13.94+00:00

Screenshot 2026-10-01 at 4.53.17 PM

Screenshot 2026-10-01 at 5.14.29 PM

I am using Microsoft Word, excel & powerpoint on a Mac, and Word is not opening/activating properly. Whenever I try to open Word, I get the following message:

Unknown Error An unknown error has occurred. The error code is: 0x0

I have already:

  • Updated Microsoft AutoUpdate to version 4.85
  • Updated Word, Excel and PowerPoint to version 16.78
  • Restarted my Mac
  • Reinstalled Microsoft Office
  • Signed in with my Microsoft account again
  • Has microsoft student & home licence 2019

However, the 0x0 error continues to appear.

Microsoft AutoUpdate shows Word, Excel and PowerPoint as “Up To Date”, but also displays **“Upgrade Required”**next to all three applications.

Mac: MacBook Air M1 (2020) Microsoft Word: 16.78 Microsoft AutoUpdate: 4.85 Error: 0x0

What does error 0x0 mean in this situation, and what is the correct way to completely fix the Office installation/activation on macOS without losing my existing documents?

I would especially appreciate instructions for checking whether this is an Office licensing/activation issue, corrupted Office components, or an incompatible/unsupported Office version.

Microsoft 365 and Office | Install, redeem, activate | For home | MacOS
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  1. DaveM121 937K Reputation points Independent Advisor
    2026-10-01T12:25:08.9766667+00:00

    The 0x0 error is a widely reported problem with the Office apps on an Apple Mac.

    1

    What type of Microsoft Office licence do you have, is that a subscription to Microsoft 365 or a standalone version of Office like Office 2019, 2021 or 2024.

    2

    At the top left of your Apple Macbook desktop, click the Apple icon and select 'About this Mac', what version of MacOS is installed on your computer?

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  2. AI answer

    2026-10-01T11:51:36.6133333+00:00

    In this case, the 0x0 error is most likely a licensing issue, not document corruption.

    The key detail is Office Home & Student 2019 for Mac together with “Upgrade Required” in Microsoft AutoUpdate. Starting July 13, 2026, Office apps on macOS can enter reduced functionality mode when the required licensing update is no longer supported. For Office 2019 for Mac, Microsoft states that it can no longer be updated to the required version, and reinstalling Office 2019 does not restore activation for editing, saving, or creating files. The 0x0 error is part of that activation failure.

    Existing documents are not deleted or damaged by this issue.

    What to check:

    1. In Word, open Word > About Word.
    2. Confirm that it shows Office 2019 and not Microsoft 365 or Office 2024.
    3. If it is Office 2019 for Mac, that identifies the issue as an unsupported licensing state rather than a corrupted installation.

    What the “Upgrade Required” message means here:

    • Microsoft AutoUpdate can show the apps as Up To Date for the installed build while still indicating Upgrade Required because the installed Office version is no longer sufficient for continued activation.
    • Since Office 2019 for Mac cannot be brought forward to the required supported state, reinstalling the same product does not fix 0x0.

    What to do next:

    1. If Office was installed from microsoft.com, close all Office apps and open Microsoft AutoUpdate from Finder > Applications > Microsoft AutoUpdate.
    2. If Office apps were installed from the App Store, update them from the App Store > Updates instead.
    3. If the apps are already fully updated and the product is still Office 2019 for Mac, there is no further activation repair path in the provided guidance.

    Available options:

    • Use Word, Excel, and PowerPoint for the web.
    • Move to a supported version such as Office Home 2024.
    • Subscribe to Microsoft 365.

    If Microsoft AutoUpdate itself is not running correctly in the background, verify it is enabled:

    1. Open System Settings.
    2. Go to General > Login Items & Extensions.
    3. Under Allow in the Background, turn on Microsoft AutoUpdate.
    4. If Microsoft AutoUpdate is missing, reinstall it using the public installer in the support article.

    This does not remove or alter existing documents. The issue is activation and support status, not file loss.

    AI-generated content may be incorrect. Read our transparency notes for more information.

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