Fatal Error C1854

cannot overwrite information formed during creation of the precompiled header in object file: 'filename'

You attempted to specify the /Yu option (use precompiled header) for a file after having specified the /Yc option (create precompiled header) for that same file previously.

If the file contains certain types of declarations (such as declarations that include the __declspec dllexport modifier), this particular usage of precompiled headers is illegal. You must restructure your .MAK file to avoid specifying /Yu on a file that was previously compiled /Yc.