diff --git a/Desktop_Interface/Labrador.pro b/Desktop_Interface/Labrador.pro
index dd32b38f..2f16e7df 100644
--- a/Desktop_Interface/Labrador.pro
+++ b/Desktop_Interface/Labrador.pro
@@ -98,10 +98,12 @@ win32{
         message("Building for Windows (x86)")
         CONFIG(release, debug|release): LIBS += -L$$PWD/build_win/libusbk/bin/lib/x86/ -llibusbK
         else:CONFIG(debug, debug|release): LIBS += -L$$PWD/build_win/libusbk/bin/lib/x86/ -llibusbK
+        DEFINES += "WINDOWS_32_BIT"
     } else {
         message("Building for Windows (x64)")
         CONFIG(release, debug|release): LIBS += -L$$PWD/build_win/libusbk/bin/lib/amd64/ -llibusbK
         else:CONFIG(debug, debug|release): LIBS += -L$$PWD/build_win/libusbk/bin/lib/amd64/ -llibusbK
+        DEFINES += "WINDOWS_64_BIT"
     }
     INCLUDEPATH += $$PWD/build_win/libusbk/includes
     DEPENDPATH += $$PWD/build/win/libusbk/includes