Last reviewed on October 27, 2014   —  19 Comments

Arguably the best feature introduced in Outlook 2010 was support for multiple Exchange mailboxes within a single Outlook profile.

Before we begin discussing that feature, let’s introduce a couple of concepts. The first is called “message fidelity”. It’s fun to say. :) The basic concept is that a message created by Outlook can have many attributes associated with it: custom forms, importance, rights management, categories, follow-up flags, voting buttons – the list goes on and on. These attributes are not, strictly speaking, part of the message – they are part of the envelope (carrying on with the metaphor of a postal message). In order for a message to have full fidelity, it must be created by Outlook, sent via MAPI, processed by Exchange, received via MAPI, and displayed by Outlook. If anything non-Microsoft gets in the way, there will likely be a reduction in message fidelity. That is, “something” may get lost.

Note that message fidelity is a pretty technical topic and is dependent on many variables. There are things that can be done in order to improve message fidelity when using non-Microsoft solutions. That being said, they are not configured by default and your average user will probably not be aware of those options.

The next concept is the idea of a “primary mailbox”. Traditionally, Outlook treated one mailbox connection as the primary connection. It was through the primary connection that all calendar reminder and task reminder notifications occur. It was also through the primary mailbox that all new mail notifications occur. This means that if you had multiple mailboxes being accessed through your profile, only one of them would receive notifications for new mail, calendar reminders, and task reminders.

In versions of Outlook prior to Outlook 2010, any Outlook profile was restricted to having only a single Exchange (MAPI) mailbox entry. And, if you had an Exchange mailbox entry in the profile, it was always considered the primary mailbox entry.

Now, Outlook did (and it still retains these features) have a couple of other features that allowed you to “work around” this limitation. First, it was possible to open additional connections to your Exchange server(s) using either IMAP or POP3. This was possible within the same profile. However, there were serious limitations associated with this. IMAP and POP3 don’t retrieve messages in full fidelity. These additional connections were also not treated as primary mailboxes. Also, IMAP and POP3 only support email – therefore calendars, tasks, contacts, etc. have to be in local storage (a PST file) and can’t be accessed from anywhere else.

Secondly, Outlook does allow a profile to specify to “open additional mailboxes”. These are mailboxes that the opening user has “full control” permissions to. However, these are not primary mailboxes. Therefore calendar reminders, task reminders, and new mail notifications do not occur.

Now, Outlook 2010 provides you with full capability to open multiple Exchange mailboxes. All of the mailboxes have full message fidelity and you have access to all of the content in all of those mailboxes (that is, you don’t need a PST for calendars, tasks, contacts, etc.). All of the Exchange mailboxes are treated as primary mailboxes, so you get all your reminders and notifications. All of the Exchange mailboxes can also be cached locally into an OST for speedy offline access.

So, if you have not yet considered an upgrade to Outlook 2010 – I recommend it. This one feature makes it worth the money. Plus, there are lots of other changes to Outlook 2010 that help improve the value proposition even more. You can download a timelocked demo from


  1. Deborah says

    I need assistance on setting up the exchange for my home computer. I purchased outlook 2010 and cannot get pass the step below. The sofwware does not run where you will see Outlook. I've read several discussions but too confusing to understand what to do. Any simple steps??

    Microsoft exchange
    Microsoft exchange server: I used
    mailbox: I used my hotmail email address

    when i select check names it responds can not connect to server

    • Diane Poremsky says

      if you use Hotmail, you don't use Exchange server. You either use POP3 or the Hotmail Connector. See Online services for POP3 configuration and a link to download the Hotmail connector.

  2. Dave L. says

    Is there a way to have a single "View" of multiple Exchange Inboxes? iPhone & Android(s) provide an aggregate view of multiple Exchange Inboxes.

  3. Scott says

    This worked great for showing the sender email address. I want to do this for the recipient address and used your instructions on creating/modifying the CFG file. Please see below script. This did not work. Can you please assist?

    ;**********The CFG file**********
    DisplayName=To Email Address
    Comment=This forms allows the Recipients E-mail address to be viewed as a
    Owner=Neostorm Systems
    DisplayName=To E-mail Address
    ;**********END CFG

    • Diane Poremsky says

      The To field in the Sent folder is not supported because of the way outlook resolves the address (and its a multivalue field), the To field in the Inbox is not supported because its a multivalue field.

  4. Scott says

    Is there some other way to achieve this without custom forms? Seems almost impossible to believe a program like Outlook, devoted to email, does not have a way to just display the email address without the display name. Are there any third party add-ins or anything else? Please advise. Thanks.

    • Diane Poremsky says

      I think i have a macro here that adds a custom field with the email address as the value - I'll see if i can find it.

    • Diane Poremsky says

      I don't know what I was thinking - if the CFG can't access the property, neither can VBA. :( The recipient email address isn't exposed in the email properties in the Sent folder - if you look at the message using MFCMAPI or OutlookSpy, the display name is shown but not the address.

  5. Scott says

    How come I can access this under the Recipient Table in OutlookSpy. If it is there, it would seem there is some way to extract it from there.

  6. Scott says

    Is it possible for you to create and email to me in a zip file? I will try that. I am not sure what else to do. If you can, can you please make the adjustment so that only the addresses in the To field are displayed? Thanks again.

  7. Scott says

    Thank you. This works but only for outgoing email. Is there a way to make this automatic for both incoming and outgoing email?

    • Diane Poremsky says

      Correct, watches for outgoing email. If you added the CFG, that will show you the sender address.

  8. Scott says

    Ok strange, it does seem to work automatically when I file them but the recipient address does not show up when they come into my inbox. Since the sorting of my emails in my file, not inbox, is the main issue, this will work perfectly. Thank you so much. I am hope other people find this post because I have read about a lot of people online trying to figure out a way to do this.

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