title: How to solve Error 26: Error Locating Server/Instance Specified in production environment?
body: <p>I have a strange error in production environment BUT not in develop environment. 
  In my develop environment, with Visual studio 2010, i can connect without problem to Sql Server 2012. 
  When i copy my Windows Form app to others PC in the same network, i get an "Error 26:Error Locating Server/Instance Specified".</p>
  
  <p>The same application worked good with an old database instance with Sql Server 2008.
  I don't know what to check and where to start!</p>
  
  <p>EDIT: Another strange behavior is that it works good if i use   a code like this</p>
  
  <pre><code>conn.Open()
  
  dr = cmd.ExecuteReader()
  </code></pre>
  
  <p>But stop to work if i open a form with a datagridview, a dataset and a BindingSource !</p>