This is a common issue for M365 applications on Mac’s, Office 365 local applications such as Word are, at times, unable to detect that they are activated.

What is the cause “Editing Not Allowed” on Office Applications on Mac

The problem lies with the software’s ability to detect correct licenses, which stops users from editing their documents.

The Fix

Option 1:

Back end files have not been fully removed.

On a Mac to fully uninstall and remove back end files you need to download a tool from the link below:

How to remove Office license files on a Mac (microsoft.com)

Once the tool is done, Download from App store after and sign in.

Option 2:

If the problem persists, uninstall and re-install M365

  1. Open Finder and click on Applications
  2. Press the Command COMMAND key click to select all of the Office applications like Word, Outlook for Mac applications
  3. Press Ctrl and click the selected applications. Then click Move to Trash from the options window
  4. Log into the M365 portal http://portal.office.com, and reinstall M365

Option 3:

Have the user log out and back into their M365 account so the system recognizes the license

  1. User will want to close all M365 applications (locally installed and web version).
  2. Log out of their M365 account using this link: http://portal.office.com
  3. On the top right they should either see their initials or a profile picture, click on that and choose the sign out option on the menu
  4. Open the Library folder (*If using a more recent OS* Go to Finder and at the Go menu, press option key and click on Library) and then open Group Containers and move these files to Trash if they are present
    1. UBF8T346G9.ms
    2. UBF8T346G9.Office
    3. UBF8T346G9.OfficeOsfWebHost
  5. They can now use the same portal link to sign back into the M365 account and launch the Office applications without issue (hopefully).

Also see this article:

https://softwarekeep.com/help-center/how-to-activate-microsoft-office-for-mac