C# - Application gets suspended on startup after boot

Question

I have an option in my application to boot on startup. This used to work fine, but now it doesn't work anymore like it should. When I check the Task Manager right after booting up the system, I can see that the application boots, gets suspended and killed by Windows.

I use the following piece of code to set the Registery key:

private void checkBox_startOnBoot_CheckedChanged(object sender, EventArgs e) //Update settings, set value of registery key
{
    if (checkBox_startOnBoot.Checked)
    {
        using (RegistryKey key = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true))
        {
            key.SetValue(Application.ProductName, Application.ExecutablePath);
        }
    }
    else
    {
        using (RegistryKey key = Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true))
        {
            key.SetValue(Application.ProductName, false);
        }
    }

    Settings.Default.Start_On_Boot = checkBox_startOnBoot.Checked;
    Settings.Default.Save();
}

I do not see anything in the Main() function that can cause the malfunction:

static void Main()
{
    if (Settings.Default.Restarting)
    {
        Settings.Default.Restarted = true;
        Settings.Default.Save();
    }
    using (oneInstanceMutex = new Mutex(false, "Global\\" + appGuid))
    {
        if (!oneInstanceMutex.WaitOne(0, false)) // If app already running, but is not restarting // && restartMutex.WaitOne(0, false)
        {
            if (!Settings.Default.Restarting)
            {
                AlreadyRunning();
                return;
            }
        }


        hpt = new HookProcThread();
        hpt.Run();

        SystemEvents.PowerModeChanged += OnPowerChange;

        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        mw = new MainWindow();
        if (Settings.Default.Restarted)
        {
            mw.WindowState = (FormWindowState)Settings.Default.RestartingWindowMode;
        }
        Settings.Default.Restarting = false;
        Settings.Default.Save();
        Application.Run(mw);
    }
}

So if anyone has an idea how I can prevent the application to get suspended and killed on boot, that would be great!

Answer 1

As it turned out, there was a file that couldn't be found. @JeroenMostert and huysentruitw both pointed me in the right direction to look in the event viewer, which showed me the error.