When using OpenFileDialog I see Assertion failed when trying to close form, how can I fix that?

Question

I have added an OpenFileDialog to my button (called "Browse") press event that should open a dialog, get a file name and return it to me.

using System;
using System.IO;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string lastFileOpenPath = "";

            using (OpenFileDialog ofd = new OpenFileDialog())
            {

                ofd.Title = "Please choose the file";
                ofd.InitialDirectory = (Directory.Exists(lastFileOpenPath) ? lastFileOpenPath : @"C:\");

                string archiveExt = "";
                for (int cn = 1; cn <= 50; cn++)
                    archiveExt += (archiveExt == "" ? "" : ";") + "*." + cn.ToString().PadLeft(3, '0');
                ofd.Filter = "Archive File (*.rar)|*.rar|Archive Files (*.###)|" + archiveExt + "|All Supported Files (*.rar, *.###)|" + archiveExt + ";*.rar";

                ofd.FilterIndex = 3;
                ofd.RestoreDirectory = true;
                if (ofd.ShowDialog() == DialogResult.OK && File.Exists(ofd.FileName))
                {
                    FilePath.Text = ofd.FileName;
                    lastFileOpenPath = Path.GetDirectoryName(FilePath.Text);
                }
            }
        }
    }
}

For some reason any time I press my Browse button (even if I do nothing and hit cancel) and then try to close the form that's open, I get the following message in the Output window. The message does not appear if I open the form, then close it. It does appear if I open the form, click the Browse button, hit cancel and then close the form.

Assertion failed: Successful WSASTARTUP not yet performed (........\src\signaler.cpp:194)

Is it possible to account for this so the "error" (if it is an error) does not appear in the Output window? I'm not asking because it's annoying, I could care less of the message in a debug output window. I'm asking because of optimization.