title: Assertion failure in -[UITableView _endCellAnimationsWithContext:] Getting Core Data error while trying to update tableview
body: <p>The application uploads the photos to the server.</p>
  
  <p>When the user selects some photos for upload, the photos' info is saved to core data. A tableview is populated showing the list of photos using <code>fetchedResultsController</code>. </p>
  
  <p>The tableview has sections for ongoing uploads, photos in queue and finished uploads and is updated accordingly based on the status.</p>
  
  <p>But now when I'm trying to add another set of photos for upload, by selecting again, while the previous set is still uploading, I get the following error.</p>
  
  <p>And the tableview goes blank after this. I cannot see anything in the tableview.</p>
  
  <pre><code>CoreData: error: Serious application error.  An exception was caught from the delegate of NSFetchedResultsController during a call to -controllerDidChangeContent:.  Invalid update: invalid number of rows in section 1.  The number of rows contained in an existing section after the update (96) must be equal to the number of rows contained in that section before the update (62), plus or minus the number of rows inserted or deleted from that section (21 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out). with userInfo (null)
  </code></pre>