Removing Email Addresses With Obsolete SMTP Domain From Users Mailboxes

Hi folks,

Just wanted to share with you a quick way to remove obsolete SMTP addresses from mailboxes in your Exchange estate.

Imagine a situation when you decommissioning a certain SMTP domain from your organization. First you perform all of the activities to prevent your environment to receive email from this domain. These activities include changes in DNS (removing MX,SPF and PTR records) and also removing accepted domains from your Exchange and hygiene appliances. Additionally you may edit your email address policies to stop provisioning decommissioned SMTP domain to the new mailboxes.

However you are still left with the mailboxes that still contain this email address in their EmailAddresses  attribute. Of course you can attend each mailbox one-by-one and scrap these addresses out, however for bigger environments it won't work.

The below script will help you to remove obsolete email addresses from mailboxes of users located in the OU contoso.com/Staff which have email addresses with adatum.com suffix. The script will go through all the users which may have this domain and scrap it out. Please note that when running this script you may need to adjust the name of the SMTP domain you're removing as well as path to the OU where mailboxes are stored.


$Mailbox = Get-User -OrganizationalUnit contoso.com/Staff -RecipientTypeDetails UserMailbox    
    $Mailbox | foreach { 
    for ($i=$_.EmailAddresses.Count;$i -ge 0; $i--) 
    { 
    $_.EmailAddresses[$i].ProxyAddressString  
     
    if ($_.EmailAddresses[$i].ProxyAddressString  -like "smtp:adatum*" ) 
    { 
    $_.EmailAddresses.RemoveAt($i) 
    } 
     
    } 
    $_|set-mailbox 
    } 

Enjoy.