unexpected nil window in _UIApplicationHandleEventFromQueueEvent

Check out your Window nib file and make sure it is taking up the full screen. I had a similar issue on my app where touch events weren't being registered on a strip on the right side. Once I set my MainWindow.xib to take up the Full Screen, I had no more errors and touch events were working again. My app was also being displayed in Landscape but my MainWindow.xib had portrait dimensions.

You don't have to add any code to fix this.

Open the main xib file and find "Window" from the left side and enable Visible at Launch and Full Screen at launch.

Additional to B H answer. Also look this answer.

Got this issue when launching my landscape only app from portrait orientation (also the app shouldn't be presented in recently opened apps list, which can be seen by pressing Home button twice. Perhaps, iOS somehow caches the orientation and window size).

My code was

self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
[self.window makeKeyAndVisible];

I set W+H autoresizing mask for window, it didn't help me, because the window don't being resized on rotation, but the transform matrix is changed.

The solution is simple

self.window = [UIWindow new];
[self.window makeKeyAndVisible];
self.window.frame = [[UIScreen mainScreen] bounds];

So the frame is set AFTER the window get its orientation from root view controller.