Dim FSO As Object
Dim FLD As Object
Dim FIL As Object
 
Set FSO=CreateObject("Scripting.FileSystemObject")
 
Set FLD=FSO.GetFolder("d:\irgendwas\deinordner\"
 
For Each FIL in FLD.Files
If Right(FIL.Name, 3)="mid" Then
FIL.Name=Left(FIL.Name, Len(FIL.Name) -3) & kar
End If
Next
 
MsgBox "Fertig"