Hi there, I made an application that has a slider, textbox and a button and I got a NSUnknownKeyException error. The app loads and then closes almost instantaneously. Here is some of the error: Code: [Session started at 2010-07-05 23:04:47 +0100.] 2010-07-05 23:04:49.078 Slider[1119:207] Unknown class SliderAppDelegate in Interface Builder file. 2010-07-05 23:04:49.082 Slider[1119:207] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UICustomObject 0x5c077b0> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key window.' *** Call stack at first throw: ( Any help would be appreciated!