SELECT Tabelle1.*
FROM Tabelle1 LEFT JOIN Tabelle2 ON (Tabelle1.Verzeichnis = _
  Tabelle2.Verzeichnis) AND (Tabelle1.Datei = Tabelle2.Datei)
WHERE (((Tabelle2.Verzeichnis) Is Null) AND ((Tabelle2.Datei) Is Null));

    Public Function TabelleA_without_TabelleB(ByVal TabelleA As List(Of _
      cFolderInfo.FileInfo_Struct), ByVal TabelleB As List(Of _
      cFolderInfo.FileInfo_Struct)) ' As List(Of cFolderInfo.FileInfo_Struct)
        Dim tempA = From A In TabelleA
                    Group Join B In TabelleB
                    On A.SubFolder Equals B.SubFolder And A.Filename Equals _
                      B.Filename
                    Into Gleich = Group
                    Where Gleich.ToList.Count = 0
                    Select A
 
        Return tempA.ToList
 
    End Function