error LNK2001: _CLSID_????

When programming with COM interface, maybe occure a LNK2001 error.
Following code makes a LNK2001 error
HRESULT hr = CoCreateInstance(CLSID_XXXXX, 0, CLSCTX_ALL, IID_XXXXX, (void**)lpVoid);

An CLSID_XXXXX defined as below.(Pressing F12)
DEFINE_GUID(..., ....)

Compiler makes an error , because compiler does not know where defined DEFINE_GUID is.

So to solve this error, you should include initguid.h header file.
#include <InitGuid.h>