title: What’s NSInternalInconsistencyException and how to deal with it?
body: <p>Often I get an <code>NSInternalInconsistencyException</code> with different error messages, can any buddy give the particular <strong>reasons and the solutions</strong> about this exception. Please provide any information, links or blogs posts about this exception. It will help me and the newcomers to overcome this problem.</p>
  
  <p>For example, I am getting the following exception messages:</p>
  
  <pre><code>"+entityForName: could not locate an NSManagedObjectModel for entity name 'Customer'"
  2nd Context already has a coordinator; cannot replace.
  </code></pre>