title: How to make ConnectionString work on client computer?
body: <p>I created a setup for a management system in Visual Studio and I used a Microsoft SQL Server database file, but when I used it on the user's computer or on another computer, I get this message when I tried to connect to the database. What is the problem?</p>
  <p>I used SQL Server 2017 Express.</p>
  <p>My connection string to work on client's PC :</p>
  <pre><code>@&quot;Data Source=.\SQLEXPRESS01;Integrated Security=True;User Instance=True;AttachDBFilename=|DataDirectory|gym.mdf&quot;;
  </code></pre>
  <p>I installed SQL Server 2017 Express on the client machine, but it didn't work.</p>
  <p>What is the problem ?</p>
  <p><img src="https://i.stack.imgur.com/EMuwt.jpg" alt="enter image description here" /></p>