I am new to this iPhone development and i have almost completed my fi
I had this same issue now and found that my sub-projects 'Public Header Folder Path' was set to an incorrect path (when compared with what my main project was using as its 'Header Search Path' and 'User Header Search Path').
e.g.
My main project had the following:
And the same for the User Header Search Paths
Whereas my sub-project (dependency) had the following:
Changing the 'Public Header Folder Path' to "../../Headers/BoxSDK" fixed the problem since the main project was already searching that folder ('../../Headers').
PS: I took some good screenshots, but I am not allowed to post an answer with images until I hit reputation 10 :(