After I upgraded to Xcode 6.1, it kept throwing this exception when I tried to build my existing application. I tried to remove \'MyController\' and add back again. But it w
You can solve it by deleting the content in the DerivedData folder. If you're worried about deleting too many folders, then delete only the folders that start with the name of your current project that you're trying to problem-solve for. Remember to close XCode before you delete the data
Library/Developer/Xcode/DerivedData/