AccessViolation occurs in RichTextBox.ScrollToCaret
public void AppendLog(string message)
    {
        try
        {
            if (this.InvokeRequired)
            {
                this.Invoke(new Action<string>(this.AppendLog), message);
            }
            else
            {
                lock (_logSyncRoot)
                {

                    if (rtbLog.TextLength > 100000)
                        rtbLog.ResetText();

                    rtbLog.AppendText(message);
                    rtbLog.ScrollToCaret();
                }
            }
        }
        catch (Exception ex)
        {
            Logger.LogException(ex);
        }
    }

at System.Windows.Forms.UnsafeNativeMethods.CallWindowProc(IntPtr wndProc, IntPtr hWnd, Int32 msg, IntPtr wParam, IntPtr lParam)
  at System.Windows.Forms.NativeWindow.DefWndProc(Message& m)
 at System.Windows.Forms.Control.DefWndProc(Message& m)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.TextBoxBase.WndProc(Message& m)
at System.Windows.Forms.RichTextBox.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.SendMessage(HandleRef hWnd, Int32 msg, Int32 wParam, Object& editOle)
at System.Windows.Forms.TextBoxBase.ScrollToCaret()
at MyApp.UI.OfflineAnalyzer.AppendLog(String message) in    D:MyAppCodeChartingOfflineAnalyzer.cs:line 339