title: Creating a Database Diagram in SSMS - Auth Failed
body: <p>I am trying to generate a database diagram from an existing SQLExpress database that I own but I am getting this error:</p>
  
  <pre><code>Database diagram support objects cannot be installed because this database does not have a valid owner.  To continue, first use the Files page of the Database Properties dialog box or the ALTER AUTHORIZATION statement to set the database owner to a valid login, then add the database diagram support objects.
  </code></pre>
  
  <p>I am the owner according to the properties:
  <img src="https://i.stack.imgur.com/vdtHL.png" alt="enter image description here"></p>
  
  <p>I did try this but was not in the correct syntax</p>
  
  <pre><code>ALTER AUTHORIZATION ON DATABASE::GuitaristDB TO PDC1\tcastonzo;
  </code></pre>
  
  <p>This executed but probably not correct</p>
  
  <pre><code>ALTER AUTHORIZATION ON DATABASE::GuitaristDB TO tcastonzo;
  </code></pre>