Happy coding !

After the installation, the linker symbol error dissapears.

It's very strange, because the application uses the default QSplashScreen without any connection to DB.

@int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QPixmap pixmap(":/images/splash");
QSplashScreen splash(pixmap);
splash.show();
splash.showMessage("Loading...", Qt::AlignBottom, Qt::white);
app.processEvents();

MainWindow w;
w.show();
splash.finish(&w);

try {
return app.exec();
}
catch (std::exception &e) {
    QMessageBox::critical(0, QLatin1String(QT_TRANSLATE_NOOP("TitleError", "Error")),
                          QLatin1String(e.what()));
    return 0;
}

}
@

I don't know what's happen and why, but, all is running again!

Now, only appears the linker symbol error message when debugging, but runs.

When the debugging starts, appears this message twice on "Application Output":

can't find linker symbol for virtual table for QSplashScreen' value found QArrayData::data()' instead

I've done a Clean All, Run qmake and Build All.

Did you only update Qt Creator ? Did you do a clean rebuild of your project ?