I had exactly the same error message as the original post. I was wrestling with this for hours.
It was this line in my AppDelegate.m.
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"[same with name of xcdatamodeld]" withExtension:@"momd"];
For anyone out there searching this error message and finding this thread….try this first.
You must make sure that where it says [same with name of xcdatamodeld]….that it is!!!
For some reason, mine had my project name in there and not the data model name.
Changed it and it worked straight away…..
Thanks to Rock & Muller for contributing…….you saved me days!!
Gaz.