@Pardeep said in Japanese letters in file path converted into question mark(?). How can i deal with them?: qDebug() This is simply debug output, it can depend on the encoding in the console. Try qDebug()<<fileName1.toUtf8()<<"\nExist: "<<f1.exists();

hi I started with http://doc.qt.io/qt-5/internationalization.html and then the "Dynamic Language Switching" from this book http://www.bogotobogo.com/cplusplus/files/c-gui-programming-with-qt-4-2ndedition.pdf On windows you can change the locale to test if it will switch. I assume you can do the same in OSX.