 <p>If you look at the very first line of your crash report, it states you are passing a nil string to NSURL's <strong>initFileURLWithPath</strong> method:</p> <pre class="lang-none prettyprint-override"><code>'NSInvalidArgumentException', reason: '*** -[NSURL initFileURLWithPath:]: nil string parameter' </code></pre> <p>From Apple documentation. </p> <p><strong>Passing nil for this parameter produces an exception.</strong></p> <p>So make sure to check your NSString before sending to <strong>initFileURLWithPath</strong> method,</p> <pre><code>NSURL* targetFileURL = nil ; if(targetFilePath != nil) { targetFileURL = [[NSURL alloc] initFileURLWithPath:targetFilePath]; } </code></pre>