Having multiple mailboxes can be a benefit for users who want to direct email to specific mailboxes based on subject material, audiences or other personal reasons. But it can also increase the workload of not only the corporate servers but of the administrators as well.

Exchange server allows users to access those multiple accounts while using only one profile and not having to re-log in under a different username. To support this functionality it is necessary for an administrator to configure Outlook such that it will enable a user to access those multiple email boxes from one profile.

An administrator should start Outlook using the profile that is configured for the Exchange server mailbox of the account (#1) that is going to be used to add a “delegate” account. Validation may be required. If so then log in to the network as the user of the account (#1). Then, follow the steps outlined below for Outlook 2002 and 2003:

1. From the Tools menu, click Options to add a delegate.
2. Select the Delegates tab and click Add.
3. Type or select a username for the delegate account (#2).
4. Click Add, and then click OK or hit enter
5. Locate the Delegate Permissions dialog boxes. Then select Editor (read, create, and modify items) in each of them.
6. Click OK or hit enter two times.
7. Click on Folder List on the View menu to make it visible.
8. Right-click the Mailbox – user name (to begin adding a new user).
9. Then click Properties for Mailbox – user name on the shortcut menu.
10. On the Permissions tab, click Add.
11. Type or select the username of account (#2) you wish to add and then click Add.
12. Click OK or hit enter.
13. From the Name box, click the newly added user for the account (#2).
14. From the Roles box, click Owner, and then click OK or hit enter.
15. Repeat steps 8 through 14 for the rest of the other folders in the mailbox.
16. On the File menu, click Exit and Log Off.

You are now ready to restart Windows and log in as the newly created username for account (#2). Once Windows has restarted you should then start Outlook with the corresponding profile for the newly created username.

Then follow these steps to add the new user for account (#2) to Exchange Server:

1. From the Tools menu, click E-mail Accounts.
2. Then click View (or change existing e-mail accounts).
3. Select the Microsoft Exchange Server and then click Change.
4. Select the More Settings button and click on the Advanced tab.
5. Click or select Add.
6. Type the username of the original account (#1) and then click OK three times.

You should be able to see the mailbox for the original account (#1) in your Folder List. The beauty of this is that your user is now able to send messages and meeting requests from the user account (#2) as if they were originating from the user of account (#1). All user (#1) needs to do is to enter the name of the user for account (#1) in the From Field. The messages sent will contain the names of the users for both accounts: one (#1) and two (#2).

Although this is a useful feature to have – multiple mailboxes – it can also be somewhat difficult to disentangle when problems occur with having multiple mailboxes.

Some users have reported that after installing a service pack update they will sometimes receive warning messages when they try to read their emails of some of these multiple accounts. The message will say something like:

“This item cannot e displayed in the Reading Pane. Open the item to read its contents.”

Double clicking the message will produce an error box which displays another message:
“Cannot open this item. Unknown Error.”

And attempts to re-add the mailbox can lead other error messages:
“The name cannot be resolved.  The connection to Microsoft Exchange is unavailable. 
Outlook must be online or connected to complete this action. “

This error message may occur even if the user is still able to send and receive emails from their primary account with the Exchange server. This type of problem can occur as a result of incorrect routing groups leftover or not fully cleaned out as a result of a recent Outlook migration. This can happen if Outlook is storing the names of the mailboxes internally with an “AD” syntax used to describe the location of the mailbox. The confusion occurs because Exchange 2007 is using a different location than the stored location in Outlook.

End users will see the effects of out of sync mailbox locations with delegates, email replies and the use of frequently-mailed-contact lists.

The cause of this out of sync mailbox location is that after a migration from Exchange 2003, each user migrated would have an attribute called “LegacyExchangeDN” that pointed to the old AD location. But a user created in Exchange 2007 did not have the same attribute. This out of sync issue can be corrected by adding a new X.500 address to each mailbox with the value of the previous “LegacyExchangeDN” attribute. Cached entries in Outlook would now be able to locate the users’ mailboxes and prevent those error messages from being generated.

In a future post I’ll discuss other issues with having multiple mailboxes and how to fix them.