' Beispiel: C:\MAPPE2.XLS (richtig!) öffnen
'''Dim bExists As Boolean
Dim oWorkbook As Object
 
' Prüfen ob Datei bereits geöffnet ist
Function bExists()
    bExists = False
    With Application
      For Each oWorkbook In .Workbooks
        If UCase$(oWorkbook.Name) = "MAPPE2.XLS" Then
          ' Jetzt aktivieren
          Windows(oWorkbook.Name).Activate
          bExists = True
          Exit For
        End If
      Next
    End With
End Function
 
' Mappe neu laden!
Sub TEST()
    If Not bExists Then
      'On Error Resume Next
      Workbooks.Open Filename:="C:\MAPPE2.XLS", ReadOnly:=False
      'On Error GoTo 0
    End If
End Sub

Gruß aus Mittelfranken
Heinz