Yes! Well, the problem removed, but this came up: Undefined symbols for architecture x86_64: "_REprintf", referenced from: Rcpp::Rstreambuf<false>::xsputn(char const*, long) in mainwindow.o Rcpp::Rstreambuf<false>::overflow(int) in mainwindow.o "_R_FlushConsole", referenced from: Rcpp::Rstreambuf<false>::sync() in mainwindow.o Rcpp::Rstreambuf<true>::sync() in mainwindow.o "_Rprintf", referenced from: Rcpp::Rstreambuf<true>::xsputn(char const*, long) in mainwindow.o Rcpp::Rstreambuf<true>::overflow(int) in mainwindow.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [] Error 1 23:51:38: Der Prozess "/usr/bin/make" wurde mit dem Rückgabewert 2 beendet. Fehler beim Erstellen/Deployment des Projekts xy (Kit: Desktop Qt 5.4.1 clang 64bit) Bei der Ausführung von Schritt "Make" Especially: symbol(s) not found for architecture x86_64 does not disappear after several tries. Here: it was described that Xcode and Mac Os were not linked properly. Here: QMAKE_MAC_SDK = macosx10.9 was suggested. Either it failed, or: Project ERROR: Could not resolve SDK path for 'macosx10.xy' was displayed! Well yet not solved... :-)