Forum Discussion
Encrypt button disappearing from Outlook
I have the same issue. Latest version of Outlook too and on business premium as well as p2 license for Security. Shows up for others but not for me and im the admin. One hint though, is I noticed if you go log into office365 then go to Subscriptions area (https://portal.office.com/account/) mine says Business Essentials which is what I used to be on. Not on that now. I suspect that's the issue.
More than likely you have both subscriptions added to your user, Business Essentials and Business Premium. Remove Business Essentials and then check to make sure that all services are turned on under the Business Premium license. If you had Business Essentials prior, you must have gotten your Office install from some other means. Office 365 Home and Student does not support the feature in Outlook. Check your version of Office.