When we setup our Exchange 2010 SP1 server, I imported ~4000 mail contacts into our system. Unfortunately, this created a GAL that our users thought was unusable, so they asked me to remove the offending contacts. I went in and deleted these from the system via EMC. I verified they are no longer in the OU I put them in. Our administrator found last night that if she emails someone from those contacts, the emails bounce, I'm guessing Exchange builds some internal fake address that receives the mail, then forwards it to the proper email address. Since I deleted these, they aren't there to forward? The Outlook clients are still showing all of those names in the address book. I went in to my %userprofile%\Appdata\Local\Microsoft\Outlook\OAB folder and deleted the OABs out of the GUIDs. When Outlook relaunched it looked okay, but when I downloaded the address book via send receive, it pulls down the dead contacts again! OWA looks okay. I deleted these contacts about 18 hours ago. I've tried the Update-GlobalAddressList command and right clicking the 'Default Offline Address Book' and clicking update. Neither seems to have helped.

Hello, It appears that the OAB may not have been rebuilt. You should try manually rebuilding it. You also need to make sure that its being replicated to the distribution points on your CAS. You also need to ensure that the users autocomplete cache is purged. (look up nk2 files). Exchange uses the LegacyExchangeDN attribute to look up addresses. This sttribute looks like: /o=your exchange org/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=something It translates that into an SMTP address when the message is sent. If it were me I would put the contacts back into exchange and then hide them from the addressbook. The reason for this is if anyone has those addresses cached in their mail clients (even if they were in old messages that they reply to) they will be re-introduced into you mail stream. If they can't be resolved they will cause new bounces to occur. Bill

The guy I had helping me setup the Exchange server got stumped, so we decided to blow away the old Default Address List and create a new one. That one is working fine (after rebooting, using a powershell command, etc). But we did find the bounce problem. I don't think it's necessary to recreate all 4000 contacts, rather, I'm going to build them by hand as requested, and hide them from the Exchange Address List. Thanks.