Some countries prefer their Exchange Address Book, displayName and cn to be:
Lastname Firstname

With Exchange 2003, this was easy to fix by following KB250455 which in short meant using adsiedit.msc to change Configuration Container -> Configuration -> cn=DisplaySpecifiers -> CN=409 and opening properties for CN=user-Display, scrolling down to createDialog and setting the attribute to:
%<sn> %<givenName>

So when you created the users with ADUC you got the expected result.

But with Exchange 2007/2010 when creating the Active Directory user with EMC (Exchange Management Console) you don’t get the expected result. Why?

Simply put – it doesn’t work. Exchange 2007/2010 simply doesn’t use the createDialog value and here’s proof.

So what solutions do Microsoft offer? Well, there’s three:

  1. Use ADUC to create the user, and then create the mailbox separately from EMC.
  2. Using EMC, make sure you manually put the Display Name correctly when creating the user:
  3. Using Powershell, make sure you specify the parameters with New-Mailbox cmdlet:

-Name “Lastname Firstname”
-DisplayName “Lastname Firstname”

To be honest, none of these settings are ideal, especially if you have many admins creating mailboxes like I do in this 20.000+ mailbox Exchange environment.

So if you already created many mailboxes with incorrect display name, you can use Amit Tank’s nice solution to do it once and he also posted a script that you can schedule every night which only edits the mailboxes created in the last 24 hours.