title: My OS X app doesn't want to open files it created
body: <p>I developed a document-based app that uses Core Data. When I start the app normally by double-clicking on it, it works perfectly and I'm able to create some data files with it. Then I'm closing the app, and trying to open the file I just created through the app, but I get the window that says:</p>
  <blockquote>
  <p>The document &quot;data.hso&quot; couldn't be opened. MyApp cannot open files of this type.</p>
  </blockquote>
  <p>I did modify the plist file to include the Document Types. As a resource I used:</p>
  <ul>
  <li><p><a href="http://daemonconstruction.blogspot.com/2012/05/drop-of-file-folder-on-dock-icon.html" rel="nofollow noreferrer">http://daemonconstruction.blogspot.com/2012/05/drop-of-file-folder-on-dock-icon.html</a></p>
  </li>
  <li><p><a href="https://developer.apple.com/library/mac/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html#//apple_ref/doc/uid/20001431-101685" rel="nofollow noreferrer">https://developer.apple.com/library/mac/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html#//apple_ref/doc/uid/20001431-101685</a></p>
  </li>
  <li><p><a href="https://stackoverflow.com/questions/2489961/dropping-files-onto-dock-icon-in-cocoa">Dropping Files onto Dock Icon in Cocoa</a></p>
  </li>
  </ul>
  <p>I'm really desperate at this moment, cause I really can't think of a reason why it shouldn't work. Any kind of help is highly appreciated!</p>
  <p>Here is the snapshot of my plist:</p>
  <p><img src="https://i.stack.imgur.com/g7i5X.png" alt="snapshot of plist" /></p>