Visual Studio warning about copies of files with different contents

Question

When I go to debug my C++ project in Visual Studio, up pops a little warning dialogue box that tells me:

A copy of datum.h was found in
c:/users/brad/desktop/sou         


        

Answer 1

Just encountered this. In my case, one of my .h files contained implementation (a class with static methods), which was #included by one of my .cpp files, but the Project Settings were also telling Visual Studio to compile the .h file.

I manually edited both the .vcxproj and .vcxproj.filters project files, moving the .h file from the ItemGroup to the ItemGroup.

This did the trick for me; I never saw the "A copy of...is different from..." pop-up again.
(Note that this was after I had thoroughly failed in attempts to get to work.)