I have recently deleted a mailbox as the mailbox was corrupt. I have now re-created with the exact details as before but a hand full of users when sending a message to that particular user get a "message undeliverable " This only happens when they use their own NK2 file. If they pick from the global address list it works fine. I have removed from the users NK2 file but still every now and again this happens. I shouldn't have to say to make sure they pick from the global address book? Any help here would be greatly appreciated

You should be able to fix it by assigning the DN from the old mailbox user to the new mailbox user as an X500 address (proxyAddresses). You can find the DN by looking at the reply address on an old email sent from the original mailbox user. Alexei

The best way to have dealt with this would be to leave the original mailbox in place, and simply forward it to the new mailbox. Hide the old mailbox from the GAL. That leaves all old links working correctly - so not just nicknames but replying to old email, but their use will die out over time. The X.500 method should work, but I have found it to be unreliable at times, and you are still stuck with the OAB regeneration time before it takes full effect (new account seen etc). The forward from the old account to the new one is immediate. Simon.Simon Butler, Exchange MVP. http://blog.sembee.co.uk , http://exbpa.com/

Hi James, Alexei and Sembee both gave some goode way to resolve the issue. Per your description, you have make a test through remove the NK2 file, but the issue still exist, right? If sounds odd, :), as normal the nickename cach the old legacyexchangedn, so if you send email use the cach, and would be failed, if we delete it, and everything would be ok. Could you please test again through the way, or just delete the special item to make a test. Some information for you: http://support.microsoft.com/kb/287623 Other possible cause maybe the replication delay. As we known, if you have too many clients, it is not a good way for all the clients, use other method as refered above maybe a good way. Regards! Gavin