We are running Exchange 2003 W/ SP2 installed. We currently had our mailbox store setup on fiber channel storage which we are migrating away from to our new iSCSI storage. We setup a new mailbox store on our exchange server and have the database and logs on the iSCSI storage. We then moved all users connected to the old mailbox store to the new mailbox store on the same server. After we removed users mailboxes we have a total of 3 mailboxes left (SMTP, System Attendant, andSystem Mailbox).When I try to remove theold mailbox store I receive the following error. "One or more users currently use this mailbox store. These users must be moved to a different mailbox store or be mail disabled before deleting this store. ID no: c1034a7f Exchange System Manager Ihave found a lot of information online that seems to be pointing at the same thing. I opened Active Directory Users and Computers and did an advance search for all users who mailbox home was on our exchange server. All the users were returned because the users still reside on the server but in a different store. I then sorted it by the store (added this column) and I still only have the three mailboxes(SMTP, System Attendant, and System Mailbox) that are part of this mailbox store. It was my understanding that if only the system mailboxes were left you would be able to remove the store and it would add the System Attendant mailbox on the other mailbox store on the server in the process. We have tried to reboot our exchange servers to make sure something was not being held in them during the mailbox move and make sure they had a clean boot under them. This still has not fixed the issue. Does anyone have any suggestions on what we may be missing to remove our old mailbox store? -------------------------------------------------------------------------------------------------------------------------------------------------------------- UPDATE: I was viewing some other exchange posts and found other users with a similar issue trying to uninstall exchange from the server. However in my case I don't want to remove Exchage Server..just remove the old mailbox store. I did look at some of the information posted and used ADSI Edit to view my Exchange Information Store. I look at the properties of the old mailbox store and at the 'homMDBBL' section. In the store I want to remove I have the following: CN=Microsoft System Attendant CN=SMTP CN=SystemMailbox CN=SystemMailbox ----------------------------------------------------------------------------------------------------------------------------------------------------------------

You may try deleting mailbox store in ADSIEdit.msc incase any other method doesnt work. But make sure that you have good AD backup incase you need to restore it.

I have noticed several different sites on the internet that made the same suggestion. However being that I am new to exchange this may sound like a dumb question. It was my understading that the Microsoft System Attendant mailbox would get moved to the new mailbox store on the server when we delete the old mailbox store. If I have to force the removal of the mailbox sotre using the method you suggested, will the System Attendant mailbox get created on the second mailbox store I have on the sever?

It recreates on second mailbox store if you delete first mailbox storenormally, refer below article for further detail. Overview of Exchange 2000 Server and Exchange Server 2003 Special Mailboxes Or you can change the homeMDB attribute of the System Attendant mailbox object with ADSIEdit to point new DB DN. Stop and restart all Exchange services to make it effective. Run cleanup agent on first mailbox store and delete disconnected SA mailbox and once it is available on new mailbox store and no error in event log then delete first unused mailbox store.