 <p>Here is an example which works well:</p> <pre><code>C:\Program Files\WinRAR&gt;rar a -hpabc h:\abc.rar c:\pdf </code></pre> <p>So you can follow the example in your codes.</p> <pre><code>p.StartInfo.Arguments = String.Format("a -hp{0} {1} {2}", your password, Destination, SourceFile); p.Start(); </code></pre>