ios - What is this iOS error and where is it coming from?

Question

My friend's app is getting an error and I do not know what to do about it.I researched this error and I came across so many different answers, but none of them seems to work.Any help will be appreciated.

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: 
'[<RootViewController 0xac80420> setValue:forUndefinedKey:]: this class is not key value 
 coding-compliant for the key optOutStatusSlider.'

Answer 1

验证您在 XIB/Storyboard 中对网点的引用，其中一个可能引用了不再存在的属性。