If you have a mistake on your code, This error may happen. I've faced the same, when I forget to pass a param, which is used inside the function. This error occurs. I've tried clear derived data, restart the mac, pod de integrate/reinstall. But still error exists. Once I checked my recently added codes one by one, I've seen the missed param. But We expect xCode will throw an error like Cannot find '' in scope . Instead of showing the error, xCode taking too much of time and struggling to build. Once added the missed params on that function, xCode build successfully. Hope It'll help. :)