Microsoft DFS Namespace explizite Rechte verwaiste ACLs löschen via cmd o. Powershell

Import-Module ActiveDirectory
# namespace to work on
$namespace = 'MyNamespace'  
# link path
$linkpath = '/EXCH'  
# get link from namespace
Get-ChildItem "AD:CN=$namespace,CN=$namespace,CN=DFS-Configuration,CN=System,$((Get-ADDomain).DistinguishedName)" | ?{$_.ObjectClass -eq 'msDFS-Linkv2' -and (Get-ADObject $_.distinguishedName -Properties 'msDFS-LinkPathv2').'msDFS-LinkPathv2' -eq $linkpath} | %{  
    # get link object properties
    $link = Get-ADObject $_.distinguishedName -Properties 'msDFS-LinkSecurityDescriptorv2'  
    # remove access rules with abandoned accounts from access list
    $link.'msDFS-LinkSecurityDescriptorv2'.Access | ?{try{[void]$_.IdentityReference.Translate([System.Security.Principal.NTAccount])}catch{$true}} | %{[void]$link.'msDFS-LinkSecurityDescriptorv2'.RemoveAccessRule($_)}  
    # replace security descriptor in property of link
    Set-ADObject $_.DistinguishedName -Replace @{'msDFS-LinkSecurityDescriptorv2'=$link.'msDFS-LinkSecurityDescriptorv2'} -Verbose  
}