Is there a way to do this with a command to remove all 125 users at one time via our Exchange Management Shell or Exchange Management Console? Or do I need to do each individually?

Probably group policy template for outlook may have this option.

Yes, you can do so in EMC and in EMS.... EMC: Use filter pane to filter the mailboxes in Recipient Configuration - Mailbox and select all and click on Disable or Remove.... How to Filter the Result Pane http://technet.microsoft.com/en-us/library/bb124566.aspx EMS: You can use -Filter parameter to filter the recipient at server side or use where{$_.parametertofilter -eq "XYZ"} client side filter to filter the result to select recipient and pipe it to Disable-Mailbox or Remove-Mailbox cmdlet... Let's say, I want to remove all the users which are member of RND group, here is the cmdlet where I used server side filtering... Get-Mailbox -filter "MemberOfGroup -eq 'CN=RND,OU=Distribution Group,DC=Domain,DC=com'" | Remove-Mailbox Reference: Working with Command Output http://technet.microsoft.com/en-us/library/bb123533.aspx Filterable Properties for the -Filter Parameter in Exchange 2007 SP1 http://technet.microsoft.com/en-us/library/bb738155.aspx And yes, make sure to check below article on handling users who are leaving org. How to deal with users leaving the Organization http://msexchangeteam.com/archive/2006/02/17/419848.aspx Amit Tank | MVP - Exchange | MCITP:EMA MCSA:M | http://ExchangeShare.WordPress.com