Hi @Suzy King,
Thank you for posting your question in the Microsoft Q&A forum.
Based on your description, I understand that Office will not activate on your Mac and you continue to receive Unknown Error 0x0. As a result, Word opens in a limited or view-only mode, and you cannot edit the documents you need for your work.
To help narrow down the issue, could you please confirm the following:
- When you mention Mac version 15, do you mean macOS 15? Please provide the complete version shown under Apple menu > About This Mac.
- What version of Word is installed? You can find this under Word > About Microsoft Word.
- Was Office installed from the Microsoft 365 website or from the Mac App Store?
- Are you using a personal Microsoft account or a work or school account?
- Does the same Microsoft 365 account activate Office successfully on another device?
Microsoft has documented the Unknown Error 0x0 / License Not Found issue on macOS. Although the issue has been marked as resolved, the Office applications must be fully updated for the fix to take effect.
If Office was installed from the Microsoft website, please try these steps:
- Close Word, Excel, Outlook, and all other Office applications.
- Open Finder > Applications > Microsoft AutoUpdate.
- If Microsoft AutoUpdate is not listed in Applications, check the following location: /Library/Application Support/Microsoft/MAU2.0/
- Open Microsoft AutoUpdate and select Update All.
- After all updates are installed, restart the Mac.
- Open Word and sign in with the account associated with your Microsoft 365 subscription.
If Office was installed from the Mac App Store, open App Store > Updates and install all available updates for Word, Excel, and the other Microsoft applications.
You can also try signing out of Office before restarting:
- Open Word or Excel.
- Sign out of your Microsoft 365 account.
- Close all Office applications completely.
- Restart the Mac.
- Reopen Word or Excel and sign back in.
For reference, please review the following Microsoft articles:
Certificate update for Microsoft 365 apps on managed macOS and iOS devices
Update Microsoft 365 or Office on your macOS or iOS device
Unknown Error 0x0 or License Not Found in Microsoft 365 or Office on macOS
If this is a work or school account and the issue continues after updating Office, your Microsoft 365 administrator may also need to confirm that an eligible Microsoft 365 Apps license is assigned to your account.
Please note that I’m also a Microsoft product user and do not have access to your account, subscription, or activation information. However, once you provide the macOS version, Word version, installation source, and account type, I will do my best to provide more appropriate guidance.
Thank you for your patience and understanding. I look forward to your update.
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