Office 365 goes to Read Only Mode
Office sometimes loses its license and tells a user it's in Read Only mode. To have Office reactivate again follow the steps below.
Open the users keychain folder in Finder at ~/Library/Keychains, ie /Users/uniqname/Library/Keychains
Look for a UUID-type folder name, ie ‘962ACF28-6B33-4ACC-9997-4F8096C8856A’ and delete it.
Reboot the computer.
Login and open Word or Excel.
On the New Document screen in the bottom left, click Activate.
Login with your Umich email address to reactivate Office.
To check how many 365 Office activations a user currently has you can login here:
Sponsored accounts with no other affiliations are not licensed to use Office on the mac.
They can use the online version at Office.com