Sub OpenLastFile()
    Dim fName As String, fOpen As String, d1
    ChDir ("C:\userdata\files\")
    fName = Dir("")
    d1 = 0
    Do Until fName = ""
        With CreateObject("Scripting.FileSystemObject").Getfile(fName)
            If .datecreated > d1 Then
                d1 = .datecreated
                fOpen = fName
            End If
        End With
        fName = Dir
    Loop
    Workbooks.Open fOpen
End Sub