O.k. that solved the issue. The problem was that the dlls had to be located in the same folder as the compiled executable. And Visual Studio 2015 does not seem to parse my environment settings for debugging PATH=%PATH%;$(SFML_PATH)\bin;$(TGUI_PATH)\bin, although it is evaluated correctly. And I already copied the TGUI and SFML dlls but not the freetype dll, which was missing. I still don't know why it complained about the TGUI dll and not the missing freetype. But anyways it runs now, thank you a lot!