 <p>In the first line in question regex: </p> <pre><code>"\\\\server1\\Cold Folder1\\(title and text number.*\\.pdf)" </code></pre> <p>error is in <code>\\Cold</code> and <code>\\(title</code> - it should have double slash <code>\\\\Cold</code> and <code>\\\\(title</code></p> <p>In the second line in question regex:</p> <pre><code> @"\\server1\Cold Folder1\(title and text number.*\.pdf)" </code></pre> <p>there are two errors: </p> <ul> <li><code>\Cold</code> should have double slash to represent slash: <code>\\Cold</code> </li> <li><code>\(title</code> mean <code>(</code>, should be <code>\\(title</code> to represent <code>\</code> and <code>StartGroup</code></li> </ul> <hr> <p>Working code:</p> <pre><code>Match m = Regex.Match("\\\\server1\\Cold Folder1\\title and text number06220-03-15-2015.pdf", @"\\\\server1\\Cold Folder1\\(title and text number.*\.pdf)"); Console.WriteLine("{0} produces the filename: {1}.", m.Groups[0].Value, m.Groups[1].Value); </code></pre>