Outlook 2011 for Mac:

User1 is configured as an Exchange User in Office365 Enterprise E1.

User1 can access to User2-Calendar (File - Open - Other User : User2 - Calendar). Only Author rights for this calendar.

When I open the calendar, I can send mails from User2 (From Field can choosen to User2)

When I delete the calendar view for User2 the From Field in email is away.

Can I prevent the User2 email-Address?