I dont know exactly what the issue is, but after looking at a couple other posts, heres the top 5 I think may be the issue, hope it helps, good luck broski
1.
I've found the most common place this error happens is when you instantiate a view from a xib from within a class that is not the xib's owner.
What I mean by this is you might be calling something similar to this:
[[NSBundle mainBundle] loadNibNamed:@"MyView" owner:self options:nil]; You're changing the owner, so you have to be sure that the class that self refers to has all the IBOutlet properties needed by "MyView". Usually this is done in Interface Builder, but in this case you're setting your owner programmatically, which means you can't make the connections in IB. When the IBOutlets aren't there, the app tries to make those connections and fails, giving the error you see.
My advice (without knowing any more info than you've given so far) is to check to see if you've made this call without having the proper IBOutlets.
2.
I had connected an UIControl outlet in the interface builder to the IBOutlet in the xib's owner. For some reason, the IBOutlet was deleted from the owner, but the reference to the outlet remained dangling in the xib. This would always give me the error Lesson learnt: When deleting any outlets for vars in the implementation, make sure to unhook the respective connection in the IB
3.
I found the problem, it was because of a button i used in the AboutViewController, i didnt declare the property for that button.
4.
Also when you rename a view, don't forget to delete the reference on File's Owner. It may also raise this error.
5.
Fixed - went to iOS Simulator > Reset Content and Setting