Exchange 2007 Legacy Mailbox Problem
I am starting to warm up to Exchange 2007 and found that anything and everything can be fixed through the Exchange Management Shell. Recently I transitioned an Exchange 2003 administrative group to Exchange 2007. After migrating the users from the Exchange 2003 to Exchange 2007, I decided to check to see if creating a mailbox is the same. So I opened the (ADUC) Active Directory Users and Computers MMC and ran through the creation of a new user and mailbox. When I went back to the Exchange Management Console the “Recipient Type Details” showed as “Legacy Mailbox”.
After searching as to why this happens or what exactly happens, it states in http://technet.microsoft.com/en-us/library/bb123981.aspx that this will happen if the 2003 tools are used. What I suspect is that certain attributes that need to be set are not when using the Exchange 2003 ADUC. When the Exchange Management Console reads the mailbox it shows a Legacy Mailbox. So uninstall Exchange 2003 tools from other administrators workstations, you can reference the Knowledge Base Article KB931747 at http://support.microsoft.com/kb/931747 if they need proof.
To rectify the “Legacy Mailbox” and convert it back to a “User Mailbox” that can be managed in the Exchange Management Console: open the Exchange Management Shell and type in ‘Set-Mailbox -Identity “Alias” -ApplyMandatoryProperties’. Replace Alias with the alias of the mailbox that can be found in the Exchange Management Console.