I got this message:
*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<FirstViewController 0x601b610> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key newCell.'
How do I solve it?
That is generally due to deleting an IB object but forgetting to delete it's links.
IE deleting a UIScrollView but forgetting to delete how it used to link into UIView through an IBOutlet.
Had the same problem earlier today... found the answer here: http://www.iphonedevsdk.com/forum/iphone-sdk-development/47036-setvalue-forundefinedkey-class-not-key-value-coding-compliant-key.html
In case that helps someone else, after checking and updating all your links between the views and the matching IBOulet, Cleaning you project can sometimes fix this issue.
来源：https://stackoverflow.com/questions/4839825/nsunknownkeyexception-this-class-is-not-key-value-coding-compliant-for-the-ke