A standard practice among most organizations when users leave, or have been let go, is to disable their associated Active Directory user account. This allows an administrator to easily re-enable the account in the event that the user comes back to work, or if someone else needs access to the account. Obviously, this has become a common practice because the process of restoring a deleted Active Directory user account is a much more complex alternative. Additionally, if these user accounts are left mailbox-enabled, you can end up with distribution groups that contain multiple disabled user accounts. This recipe will show you how to remove these disabled accounts using the Exchange Management Shell.

$groups = Get-DistributionGroup -ResultSize Unlimited
foreach($group in $groups){
 Get-DistributionGroupMember...