Quick setup:

Our company uses your first initial and last name for your Active Directory account name.

User calls in several times over the course of a couple weeks having continuous problems with permissions, accessing his own network data, etc. we resolve it time and again, several times with just password changes, other times with permissions in AD or on the network, etc. Finally, tier 2 (NOT me) decides that it his AD account causing all the problems. They are just going to remove his acct and create a new one with his middle initial in the name. Obviously this changes everything from his logon to his email.

User is notified of the problem, the fix and the changes. New account is created. Next day:

User: I am not getting my emails

Me: Let me look at what is going on. (At this point I connect to his machine, he has emails from about 3 minutes ago, and everything looks fine.) I show him the recent emails and notify him that he is clearly getting his emails.

User: People keep telling me they are sending me emails that I am not getting.

Me: (Looking at his AD account I notice the note about the new account.) Sir, you just had a new account created because of the problems you were previously having. The guy that created it noted that he spoke with you about the changes and he notified you that your email would be changing to now include your middle initial.

User: Yeah, I know that, but why aren't I getting my emails.

Me: I would guess that it is because people are using auto-complete for your email, so it would be filling in your old email address. You need to let them know that your email has changed so they can send it to the correct address.

User: Well why can't you do that?

Me: Well who would you like us to tell? How could we possibly know who you contact and how would we be able to contact them?

User: So you mean I have to tell everyone my email address changed?

Me: How else are they going to find out?

User: Well how do I know who to tell?

Me: Well why don't you start with the people that are contacting you telling you that you are not getting their email and continue on to all the rest of the people you normally have any contact with.

User: ::sigh:: god, what a pain in the ass ::click::

Me: ::shaking my head::

EDIT: Apparently I suck at explaining or people suck at reading. THIS WAS NOT DUE TO A NAME CHANGE. The name was changed because the tier above me decided he needed a new AD account. They have to give the new account a different name, check that it all works properly and then remove the old account that is hosed. The name change was a side effect NOT the main cause.