I created an empty \'Demo\' project in Visual Studio 2008 and added some existing projects to my solution. Included \"MyHeader.h\" (other project\'s header) in main.cpp file
In my experience, with VS2010, when include files can't be found at compile time, doing a clean, then build usually fixes the problem. It's not that rare for the editor to be able to open an include file and then the compiler to announce that it can't find that very file, even when it is open on the screen!