excel - Create Backup folder with max. 7 backups -

my code doesnt kill older backups after getting on 7 backups :(

---

option explicit

private sub workbook_beforesave(byval saveasui boolean, cancel boolean)
dim savepath string
dim filename string
dim fileextension string
dim filedate string
dim filebackupname string
dim fileusername string

dim datei string
dim datalt string
dim dateilösch string
dim x long
dim zähler long

if dir(activeworkbook.path & "\" & "backup", vbdirectory) = "" then
mkdir (activeworkbook.path & "\" & "backup")
end if

 savepath = thisworkbook.path & "\backup\"  filename = left(thisworkbook.name, instrrev(thisworkbook.name, ".") - 1)  fileextension = mid(thisworkbook.name, instrrev(thisworkbook.name, ".") + 1)  fileusername = environ("username")  filedate = format(now, "yyyymmdd_hhmmss")    '--- letztes backup löschen  x = len(filename & "_" & fileusername & "_") + 1  datalt = "zzz"  datei = dir(savepath & filename & "_" & fileusername & "_*." & fileextension)  while datei <> ""     zähler = zähler + 1     if mid(datei, x) < datalt         datalt = mid(datei, x)         dateilösch = datei     end if     datei = dir  loop  if zähler > 6 , datei <> "" kill savepath & dateilösch     filebackupname = savepath & filename & "_" & fileusername & "_" & filedate & "." & "_" & _  fileextension  activeworkbook.savecopyas filebackupname 

end sub

thanks