// main.cpp:
QSettings* Settings = new QSettings(".\\Settings.ini", QSettings::IniFormat);

qApp->setProperty("Settings", QVariant::fromValue<QSettings*>(Settings));

// MainWindow.cpp:
QSettings* Settings = qApp->property("Settings").value<QSettings*>();

QVarLengthArray<QVariant, 100> Servers;

Settings->beginGroup("Servers"); // <-- Crashes here
Servers.resize(Settings->beginReadArray("Server"));

for(int It = 0; It < Servers.size(); It++)
{
    Settings->setArrayIndex(It);

    QTreeWidgetItem* Server = new QTreeWidgetItem(this->Ui->MainTreeview);

    Server->setText(0, Settings->value("Name").toString());
    Server->setIcon(0, QIcon(":/Icons/Resources/Icons/server.png"));
}