Terminating app due to uncaught exception reason: 'Application windows are expected to have a root view controller at the end of application launch'

Question

FeedContentVC *feedVC= [[FeedContentVC alloc] initWithNibName:@"FeedContentVC" bundle:nil];
navigationController = [[UINavigationController alloc] initWithRootViewController:feedVC]; 
navigationController.navigationBar.barStyle = UIBarStyleBlack; 
[window setRootViewController:navigationController];

Answer 1

Although things looks correct in what you are doing, could you please confirm following:

1. window is a strong property in your AppDelegate. It should be [self.window setRootViewController:navigationController].
2. Put a breakpoint and check that feedVC is not nil.
3. You have this statement in your code [self.window makeKeyAndVisible];.

Answer 2

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
        self.window.backgroundColor = [UIColor whiteColor];
        [self.window makeKeyAndVisible];
        FeedContentVC *feedVC= [[FeedContentVC alloc] initWithNibName:@"FeedContentVC" bundle:nil];
        navigationController = [[UINavigationController alloc] initWithRootViewController:feedVC]; 
navigationController.navigationBar.barStyle = UIBarStyleBlack;
        [self.window setRootViewController:navigationController];