We have a user who has had her last name changed, and we want to rename her mailbox. That worked fine, except that the directory name on the Advanced tab still has her old name. Is there a way to change this?

A. No. In Microsoft Exchange Server, the directory name acts like the serial number on a piece of paper money—it uniquely identifies one, and only one, object. Some objects, such as X.400 connectors, let you supply a directory name when you create them; various Exchange DLLs assign the names of other objects. Once you have given an object a directory name, you can't change it. The good news is that you can change the mailbox alias and display names for your user. Exchange components use the directory name internally, but there's no rule that it has to make sense to humans; instead, use the human-readable and human-editable fields that the mail clients display.