title: Cannot use special principal dbo: Error 15405
body: <p>I am trying to give all the permissions to a user in the User Mapping section of a database. But, I am encountering this error:</p>
  
  <p>"Cannot use special principal dbo"
  <img src="https://i.stack.imgur.com/e5Svl.jpg" alt="alt text"></p>
  
  <p>Server roles of the user:</p>
  
  <p><img src="https://i.stack.imgur.com/kTGxS.jpg" alt="alt text"></p>