Ok, I’ve had this problem before. I couldn’t remember how I solved this so I searched on Google and found this question. But this time, nothing helped me. These are the things I did. I believe the last one solved this.
- Clear Derived Data. Go to Terminal and enter this:
rm -rf ~/Library/Developer/Xcode/DerivedData - Quit the whole Xcode.
- Close all tabs of Xcode and make sure to view some class files instead of Interface builder and go try again viewing assistant results.
- Remove the assigned class to the View Controller nib you think causes the problem, then assign the class again. Boom! Solved!