Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
For the macOS 0x0 error in Microsoft 365 or Office, use this update-based fix first:
- Verify the Mac is running macOS 12 or later.
- Close all Office apps.
- Open Finder > Applications > Microsoft AutoUpdate.
- If Microsoft AutoUpdate is not visible there, check:
/Library/Application Support/Microsoft/MAU2.0/
- If Microsoft AutoUpdate is not visible there, check:
- Install all available Office updates by selecting Update All, or update each app individually.
- After updates finish, open Word, Excel, Outlook, or another Office app and test again.
If the Office apps were installed from the App Store instead of microsoft.com:
- Close all Office apps.
- Open the App Store.
- Select Updates from the sidebar.
- Update the Microsoft Office apps.
- Open the app again and test.
If the error is specifically happening with Office for Mac 2011, the supported fix is to upgrade to the latest Microsoft 365 for Mac, then open an Office app and sign in with the Microsoft account tied to the active subscription.