When using a personal Mac you may see the error message "Your account 100123456@unimail.derby.ac.uk doesn't allow editing on a Mac. To learn more, contact your admin about your Office plan." To solve this issue you need to:
- Open Finder -> Applications -> Utilities -> Keychain Access.
- Remove the following application passwords.
- Unknown
- Microsoft office identities cache 2
- Microsoft office identities settings 2
- Search for all occurrences of adal in the keychain and ,if present, remove all the entries. - Restart Mac.