Quote Originally Posted by lyuts View Post
After adding new cpp/h files run "qmake -project", then "qmake" and then "make" again.
If he's adding the files through Creator then there is no need to do that. And please don't advise people to run qmake -project while in the middle of the development process. This command should (if at all) be ran only once at the very beginning of development, just before the first compilation and never again later.