How to disable automatic client authentication
By default, after Tableau Desktop clients first successfully sign in to Tableau Server, they are automatically authenticated in the future. As a Tableau Server administrator, however, you can disable automatic authentication.
To immediately disconnect all clients from Tableau Server and require users to sign in every time they connect:
In the site menu, click Manage All Sites, and then click Settings > General.
Under Connected Clients, clear the option Allow clients to automatically connect to Tableau Server.