title: CoreData could not fulfill a fault
body: <p>I have a problem with the CoreData and fulfilling managedObjects.</p>
  
  <p>Stack trace:</p>
  
  <pre><code>Uncaught exception: CoreData could not fulfill a fault for '0x11cec410 &lt;x-coredata://08BF0B39-BA5D-404E-B75E-FD4FA906DE3E/TaskDescription/p1747&gt;'. Stack trace: (
  "4   libc++abi.dylib                     0x03553f60 _ZSt11__terminatePFvvE + 14",
  "5   libc++abi.dylib                     0x03553b97 __cxa_rethrow + 103",
  "6   libobjc.A.dylib                     0x02cb0a57 objc_exception_rethrow + 47",
  "7   CoreFoundation                      0x02f95bc5 CFRunLoopRunSpecific + 613",
  "8   CoreFoundation                      0x02f9594b CFRunLoopRunInMode + 123"
  </code></pre>
  
  <p>)</p>
  
  <pre><code> *** Terminating app due to uncaught exception 'NSObjectInaccessibleException', reason: 'CoreData could not fulfill a fault for '0x11cec410 &lt;x-coredata://08BF0B39-BA5D-404E-B75E-FD4FA906DE3E/TaskDescription/p1747&gt;''
  *** First throw call stack:
  (
  0   CoreFoundation                      0x02ff05e4 __exceptionPreprocess + 180
  1   libobjc.A.dylib                     0x02cb08b6 objc_exception_throw + 44
  2   CoreData                            0x0298666b _PFFaultHandlerLookupRow + 2715
  3   CoreData                            0x02985bc7 -[NSFaultHandler fulfillFault:withContext:forIndex:] + 39
  4   CoreData                            0x029857a3 _PF_FulfillDeferredFault + 259
  5   CoreData                            0x029855f6 _sharedIMPL_pvfk_core + 70
  6   CoreData                            0x0298a005 -[NSManagedObject(_PFDynamicAccessorsAndPropertySupport) _genericValueForKey:withIndex:flags:] + 85
  7   CoreData                            0x029c3ab1 _PF_Handler_Public_GetProperty + 161
  8   CoreData                            0x029c39b5 -[NSManagedObject valueForKey:] + 149
  9   Foundation                          0x0254e065 -[NSFunctionExpression expressionValueWithObject:context:] + 1260
  10  Foundation                          0x025d4109 -[NSComparisonPredicate evaluateWithObject:substitutionVariables:] + 248
  11  Foundation                          0x025d4009 -[NSPredicate evaluateWithObject:] + 48
  12  CoreData                            0x02a8f991 -[NSFetchedResultsController(PrivateMethods) _objectInResults:] + 113
  13  CoreData                            0x02a912c2 -[NSFetchedResultsController(PrivateMethods) _preprocessUpdatedObjects:insertsInfo:deletesInfo:updatesInfo:sectionsWithDeletes:newSectionNames:treatAsRefreshes:] + 642
  14  CoreData                            0x02a926f4 -[NSFetchedResultsController(PrivateMethods) _managedObjectContextDidChange:] + 1892
  15  Foundation                          0x02622e39 __57-[NSNotificationCenter addObserver:selector:name:object:]_block_invoke + 40
  16  CoreFoundation                      0x0304c524 __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 20
  17  CoreFoundation                      0x02fa407b _CFXNotificationPost + 2859
  18  Foundation                          0x0255cb91 -[NSNotificationCenter postNotificationName:object:userInfo:] + 98
  19  CoreData                            0x029974a3 -[NSManagedObjectContext(_NSInternalNotificationHandling) _postObjectsDidChangeNotificationWithUserInfo:] + 83
  20  CoreData                            0x02a36abf -[NSManagedObjectContext(_NSInternalChangeProcessing) _createAndPostChangeNotification:withDeletions:withUpdates:withRefreshes:] + 367
  21  CoreData                            0x02993168 -[NSManagedObjectContext(_NSInternalChangeProcessing) _postRefreshedObjectsNotificationAndClearList] + 136
  22  CoreData                            0x02992d14 -[NSManagedObjectContext(_NSInternalChangeProcessing) _processRecentChanges:] + 3140
  23  CoreData                            0x029920c9 -[NSManagedObjectContext processPendingChanges] + 41
  24  CoreData                            0x02966311 _performRunLoopAction + 321
  25  CoreFoundation                      0x02fb853e __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 30
  26  CoreFoundation                      0x02fb848f __CFRunLoopDoObservers + 399
  27  CoreFoundation                      0x02f963b4 __CFRunLoopRun + 1076
  28  CoreFoundation                      0x02f95b33 CFRunLoopRunSpecific + 467
  29  CoreFoundation                      0x02f9594b CFRunLoopRunInMode + 123
  30  GraphicsServices                    0x0488d9d7 GSEventRunModal + 192
  31  GraphicsServices                    0x0488d7fe GSEventRun + 104
  32  UIKit                               0x016c294b UIApplicationMain + 1225
  33  MYAPP                              0x0003bb9d main + 141
  34  MYAPP                              0x00003055 start + 53
  )
  libc++abi.dylib: terminating with uncaught exception of type _NSCoreDataException
  </code></pre>
  
  <p>All I can see when app crashes is that trace with only showing some internal CoreData/Foundation instructions. Can anyone please explain me, what is going on with that</p>
  
  <pre><code>NSFetchedResultsController(PrivateMethods)
  </code></pre>
  
  <p>or</p>
  
  <pre><code>NSManagedObjectContext(_NSInternalChangeProcessing)
  </code></pre>
  
  <p>It looks very weird to me. How can I prevent from such NSObjectInaccessibleException?
  I know that this error is due to previously deleted object. I have many background contexts run asynchronously, but I think that I am keeping the rules given by Apple documentation about concurrency with CoreData. It crashes only sometimes and I can't see anything from this point. Anyone had similar situation?</p>