QFileSystemModel setRootPath

Did you try forcing the index to show the directory ?

listView->setRootIndex(dirModel->index("/Users"));

This works fine for me:

#include <QtGui>

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QFileSystemModel model;
    model.setRootPath("/Users");
    QListView view;
    view.setModel(&model);
    view.setRootIndex(model.index("/Users/"));
    view.show();
    return app.exec();
}

This code has worked for me as well:

QFileSystemModel *dirModel = new QFileSystemModel(this);
dirModel->setRootPath("/Users");

ui->listView->setModel(dirModel);
ui->listView->setRootIndex(dirModel->setRootPath("/Users"));