Microsoft 365 on macOS read-only issue

Problem

You encounter a “read-only mode” message upon launching any Microsoft 365 apps.

Solution

Try the following solutions in order, starting with the simplest option.

1.  Sign out and sign back in with your Douglas College account.

If the issue persists, continue to the next step.

2.  Manually remove cached credentials.

• Open each installed Microsoft 365 app (e.g., Word, Excel, PowerPoint), click the app name menu (e.g., PowerPoint) and select Sign Out. Then quit the application.
• Open Finder, click on the Go menu item and choose Go to Folder
• In the dialog box, type: ~/Library and press Enter
• Open the Group Containers folder
• Locate the following three files/folders and move them to Trash:
  • UBF8T346G9.ms
  • UBF8T346G9.Office
  • UBF8T346G9.OfficeOsfWebHost
• Empty the Trash and launch a Microsoft 365 application, sign in with your Douglas College email address and check to see if you can now edit documents.

If the issue persists, continue to the next step.

3. Remove Microsoft 365 license files

• Fully remove the Microsoft 365 license from your macOS computer by following this Microsoft's instructions: https://support.microsoft.com/en-ca/office/how-to-remove-office-license-files-on-a-mac-b032c0f6-a431-4dad-83a9-6b727c03b193.
• The Microsoft license removal tool is available through the Microsoft Support article above. After removing the license files, open a Microsoft 365 application and sign in with your Douglas College account.

4. Update your MacOS version

• Microsoft 365 supports only the three most recent major versions of macOS. If your Mac is running an older version, Microsoft 365 may enter reduced functionality mode, which can prevent you from editing or saving documents.

  Check for available macOS updates and install the latest version supported by your Mac.

5. Uninstall Microsoft 365 Apps Completely

• If none of the above steps resolve the issue, completely uninstall Microsoft 365 from your Mac and reinstall the applications: https://support.microsoft.com/en-ca/office/troubleshoot-office-for-mac-issues-by-completely-uninstalling-before-you-reinstall-ec3aa66e-6a76-451f-9d35-cba2e14e94c0