After upgrading Xcode from 5 to 6 beta, almost every project gives me an unexpected error after running the application. There are some other posts with this title but the error
I'm new to the coding world but resolved the painstacking problem. I was getting the same error by doing something and even though i deleted everything around that i couldn't resolve it. It was still giving me the same error, which meant that it is not deleting in some file it stores. Took me a while to figure out which file, finally when i opened the Mainstoryboard as source file, and did search on the error key word which i knew i changed, it gave me the lines it was sitting in. After deleting those lines error got fixed. I know basic HTML so i knew which lines to delete.
I cannot start my project all over again everytime i have this error so i had to find the solution and there was no solution i could find. So i had to do it myself with common sense, as i said i have no knowledge of coding.
Hope it helps.