I check if the info of the file exists. It does not, it says that the file doesn’t exist but as soon as i delete the check line the filename is printed onto the QTableView.
(the file exists in the dictionary)

void printOutput(std::set<std::string> files, QStandardItemModel* model)
{

    model->setRowCount(files.size());
    int row = 0;

    for (const auto& str : files)
    {
        const auto fname = QString::fromStdString(str);
        QFileInfo info(fname);

        if (!info.exists())
        {
            QMessageBox::warning(nullptr, "printOutput", QString("%1 don't exist").arg(fname));
            continue;
        }

        const auto dateTime = info.lastModified();
        auto* dateItem = new QStandardItem(dateTime.toString());
        auto* fileItem = new QStandardItem(fname);

        model->setItem(row, 0, dateItem);
        model->setItem(row, 1, fileItem);

        row++;
    }
}

I added the if-statement to check whether there is a info for the file. I expected it to go through and print the info (Date & Time of last modification). But the QMessageBox with the warning got shown.