Xcode: How do I change my project folders name, without having building problems?
Select Product > Clean from the Xcode menu.
Then try and build again by selecting Product > Build.
Your project should build without errors assuming that targets are correct.
Either you have replaced the code to some another machine. Try to commit the explicitly included import in the .PCH file. Compile it once on that specific machine. Now un-comment the those import lines and then compile the code again.
If you are trying to build project from terminal then
execute "$ xcodebuild clean " before execute the build command.
This will resolve the issue.