There was a change in Outlook 2010/2013 that all configured mail accounts will get their own Personal Folders list (pst-file) or mailbox. By doing so, all mail data is automatically separated for each account.
When you want to monitor all your POP3 accounts from a single mailbox in Outlook, you are going to need to change the delivery location on all those other email accounts.
- Open the Account Settings dialog; File-> Account Settings-> Account Settings…
- Select the POP3 account for which you want to change the delivery location.
- Press the “Change Folder” button at the bottom of the dialog.
- 4. Select the folder to which you want your new messages delivered for that account.
This can be an already existing folder such as the Inbox of your main mailbox or a separate (sub) folder.
There you go, you have tamed the Outlook inbox beast.