Never forget qmake

Oh come on! Error again! I encounter a weird error on QT compiler today. I though I had the thing fixed on last week, wonder why the fix on last week is not working on today? What a joke. Now the error is different. The error mentions that I have multiple definition found. The root cause is coming from the Boost library.

13:12:11: Starting: "D:\tool\Qt\Tools\QtCreator\bin\jom.exe" 
 D:\tool\Qt\Tools\QtCreator\bin\jom.exe -f Makefile.Debug
 cl -c -nologo -Zc:wchar_t -FS -Zc:strictStrings -Zc:throwingNew -Zi -MDd -GR -W3 -w34100 -w34189 -w44996 -w44456 -w44457 -w44458 -wd4577 -wd4467 -EHsc /Fddebug\wqt1.vc.pdb -DUNICODE -DWIN32 -DQT_QML_DEBUG -DQT_CORE_LIB -I..\wqt1 -I. -I..\..\..\tool\boost_1_61_0 -I..\..\tool\Qt\5.7\msvc2015\include -I..\..\tool\Qt\5.7\msvc2015\include\QtCore -Idebug -I..\..\tool\Qt\5.7\msvc2015\mkspecs\win32-msvc2015 -Fodebug\ @C:\Users\HUAHS_~1\AppData\Local\Temp\main.obj.4132.31.jom
main.cpp
 link /NOLOGO /DYNAMICBASE /NXCOMPAT /DEBUG /SUBSYSTEM:CONSOLE "/MANIFESTDEPENDENCY:type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' publicKeyToken='6595b64144ccf1df' language='*' processorArchitecture='*'" /MANIFEST:embed /OUT:debug\wqt1.exe @C:\Users\HUAHS_~1\AppData\Local\Temp\wqt1.exe.4132.8453.jom
libboost_filesystem-vc140-mt-gd-1_61.lib(path_traits.obj) : error LNK2005: "void __cdecl boost::filesystem::path_traits::convert(char const *,char const *,class std::basic_string<wchar_t std::char_traits="" struct="" wchar_t="">,class std::allocator<wchar_t> > &,class std::codecvt<wchar_t _mbstatet="" char="" struct=""> const &)" (?convert@path_traits@filesystem@boost@@YAXPBD0AAV?$basic_string@_WU?$char_traits@_W@std@@V?$allocator@_W@2@@std@@ABV?$codecvt@_WDU_Mbstatet@@@5@@Z) already defined in boost_filesystem-vc140-mt-gd-1_61.lib(boost_filesystem-vc140-mt-gd-1_61.dll)
libboost_filesystem-vc140-mt-gd-1_61.lib(path.obj) : error LNK2005: "public: static class std::codecvt<wchar_t _mbstatet="" char="" struct=""> const & __cdecl boost::filesystem::path::codecvt(void)" (?codecvt@path@filesystem@boost@@SAABV?$codecvt@_WDU_Mbstatet@@@std@@XZ) already defined in boost_filesystem-vc140-mt-gd-1_61.lib(boost_filesystem-vc140-mt-gd-1_61.dll)
debug\wqt1.exe : fatal error LNK1169: one or more multiply defined symbols found
jom: D:\workspaceqt\build-wqt1-Desktop_Qt_5_7_1_MSVC2015_32bit-Debug\Makefile.Debug [debug\wqt1.exe] Error 1169
jom: D:\workspaceqt\build-wqt1-Desktop_Qt_5_7_1_MSVC2015_32bit-Debug\Makefile [debug] Error 2

How could I resolve them? I am spending hours experiment this error, by making a clean build or start a new project from scratch just to simulate this error have no result. Until late night only found out there is a very important step was missing during the build.

Whenever the PRO file is updated, I'm required to run qmake, because this will allow to update the Makefile generate by the QT. No wonder why sometimes I get an error on undefined reference on blah_blah_blah_functionA() when I add a new library in PRO file.