RS232 communication packet disruption on windows 10

<pre>Private Sub initCommPort()
        If SerialPort1.IsOpen = False Then
            SerialPort1.PortName = ListBox1.SelectedItem
            SerialPort1.BaudRate = 115200
            SerialPort1.Parity = Parity.None
            SerialPort1.DataBits = 8
            SerialPort1.StopBits = StopBits.One
            SerialPort1.ReadTimeout = 100


            'SerialPort1.ReceivedBytesThreshold = 100
            SerialPort1.DiscardNull = True

            Try
                SerialPort1.Open()
                rs232Timer.Interval = 100
                rs232Timer.Start()
                vcapMin1 = 9999
                vcapMax1 = 0
                vcapMin2 = 9999
                vcapMax2 = 0
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try
        End If
        ' ONCE PORT IS INITIALISED, RECEIPT OF DATA KICKS EVERYTHING OFF ... 
    End Sub

    ' This is the method to run when the rs232Timer is raised. 
    Private Sub TimerEventProcessor(ByVal myObject As Object, ByVal myEventArgs As EventArgs) Handles rs232Timer.Tick
        rs232Timer.Stop()
        Do
            Try
                Dim Incoming As String = SerialPort1.ReadLine()
                If Incoming Is Nothing Then
                    Exit Do
                Else
                    Dim packet As String = Incoming
                    Incoming = Nothing
                    If (RequestCmd > 0) Then
                        If SerialPort1.IsOpen = True Then
                            SerialPort1.Write(Chr(RequestCmd))
                            System.Diagnostics.Debug.WriteLine("CMD: " & RequestCmd)
                            RequestCmd = 0
                        Else
                            System.Diagnostics.Debug.WriteLine("CMD: " & RequestCmd)
                        End If
                    End If
                    Me.BeginInvoke(New StringSubPointer(AddressOf ProcessData), packet)

                End If
            Catch ex As Exception
                Exit Do
            End Try
        Loop

        rs232Timer.Start()
    End Sub

    Private Sub ProcessData(ByVal Buffer As String)
        Dim rawLine As String
        If Buffer.Length > 0 Then
            Select Case Mid(Buffer, 1, 1)
                Case "P" 'PON registers
                    processPonRegs(Buffer)
                    If (Mid(Buffer, 2, 1) = "1") Then
                        If (p1Active = True) Then
                            rawLine = Mid(Buffer, 1, 2) & " " & Mid(Buffer, 3, 16) & " " & Mid(Buffer, 19, 16) & " " & Mid(Buffer, 35, 16) & " " & Mid(Buffer, 51, 16)
                            storeRawDataLine(rawLine, 2)
                            rawLine = "   " & Mid(Buffer, 67, 16) & " " & Mid(Buffer, 83, 16) & " " & Mid(Buffer, 99, 16) & " " & Mid(Buffer, 115, 16)
                            storeRawDataLine(rawLine, 3)
                        End If
                    Else
                        If (p2Active = True) Then
                            rawLine = Mid(Buffer, 1, 2) & " " & Mid(Buffer, 3, 16) & " " & Mid(Buffer, 19, 16) & " " & Mid(Buffer, 35, 16) & " " & Mid(Buffer, 51, 16)
                            storeRawDataLine(rawLine, 4)
                            rawLine = "   " & Mid(Buffer, 67, 16) & " " & Mid(Buffer, 83, 16) & " " & Mid(Buffer, 99, 16) & " " & Mid(Buffer, 115, 16)
                            storeRawDataLine(rawLine, 5)
                        End If
                    End If
                Case "T" 'Trace Buffer Data
                    'saveTraceBufferLine(Buffer, TBConfiguration)
                    My.Computer.FileSystem.WriteAllText("TraceBuffer.txt", Buffer, True)
                    rawLine = Buffer
                    storeRawDataLine(rawLine, 6)
                    TBLine = TBLine + 1
                Case Else 'Status data
                    If Mid(Buffer, 4, 1) = "S" Then
                        processStatus(Buffer)
                        rawLine = Mid(Buffer, 4, 1) & "  " & Mid(Buffer, 5, 16) & " " & Mid(Buffer, 21, 16) & " " & Mid(Buffer, 37, 16) & " " & Mid(Buffer, 53, 16)
                        storeRawDataLine(rawLine, 1)
                        displaySerialNumber()
                        displayFirmware()
                        displayAlarms()
                        increment(nscans1)
                        ProgressBar1.Value = nscans1
                    End If
            End Select
        End If
    End Sub