In Microsoft Outlook 2003, 2007, 2010, and 2013 (beta), you can add multiple Microsoft Exchange mailboxes by going into your Outlook account, and adding mailboxes like so:


However, when you send email messages from one of these additional mailboxes, you’d notice that your sent items would go into your primary mailbox’s sent items. This is a bug in Outlook. However, there is a hotfix for Outlook 2003, 2007, and 2010 to resolve this issue. For these versions of Microsoft Outlook, you can download the appropriate hotfix below:

After that is applied, a registry key needs to be added. The key that is added needs to be in HKEY_CURRENT_USER\Software\Microsoft\Office\{OfficeVersion}\Outlook\Preferenceswhere {OfficeVersion} is the following:

  • Outlook 2003 – 11.0
  • Outlook 2007 – 12.0
  • Outlook 2010 – 14.0
  • Outlook 2013 – 15.0

The key to add is a DWORD key named DelegateSentItemsStyle. The value for this key should be 1.

Using Outlook 2010 or Outlook 2013

If you are using Outlook 2010 or Outlook 2013, there’s a better solution. Starting in Outlook 2010, the application would allow you to add more than one Microsoft Exchange mailbox per profile. This solves this issue without applying these hotfixes.