Problem solve Get help with specific problems with your technologies, process and projects.

When a mailbox gets reconnected to the wrong user account

After an administrator rebuilt an Exchange server from scratch, some users were unable to access their e-mail and no longer appeared on the Global Address List. SearchExchange.com expert Bharat Suneja explains how to correct these problems by re-associating the users' mailboxes with the proper accounts.

We recently had to rebuild our Microsoft Exchange server from scratch, which included reinstalling both Exchange...

and Windows. We also mounted the current information store into a new store, and reconnected the users' mailboxes to their accounts.

Now, one or two users are unable to access their mail, and no longer appear on the Global Address List. It seems that they have valid user accounts in Active Directory, although they don't have any Exchange server or mailbox store specified. They also have existing mailboxes which are listed in Exchange System Manager.

Despite running the cleanup agent in Exchange System Manager, neither the reconnect nor purge options are available on any of these mailboxes. I need to find a way of reconnecting an existing mailbox with an existing user in the Active Directory. Any suggestions?

This may have happened if the mailbox got reconnected to the wrong user account, and you may not have noticed it because the account it got reconnected to is not ordinarily supposed to be mailbox-enabled.

Before doing anything, let's check if the mailbox has been accessed by a user. In Exchange System Manager, you can check the "Last logged on by" column next to the mailbox to check which account logged on to it last. Also check the "Last logon time" -- has it been accessed recently?

If it appears that it hasn't been accessed at all since you restored, you can right click on the mailbox, select Exchange Tasks to start the Exchange Task Wizard, and select "Delete mailbox" from the task selection dialog box. Don't panic -- this does not actually delete the mailbox!

Run the cleanup agent and you will see the mailbox is now marked with the red x icon which means it is a deleted mailbox. Now you can right click the mailbox and reconnect it to any user that is not already mailbox-enabled.

Do you have comments on this Ask the Expert Q&A? Let us know.

Dig Deeper on Exchange Server setup and troubleshooting