When the account has its own folder set, all the emails are automatically stored in the corresponding folders without the need for configuring anything else like for instance rules. This dedicated folder set contains the following default folders While this guide is mainly focused on separating mails received from different accounts, the techniques can be used to sort mail based on other criteria as well. This guide introduces that and several other techniques which you can use to sort your email based on the account you have received it with. This allows you to still use only a single pst-file but still separate the incoming emails from each account. It also has an option which lets you decide which folder the emails should be delivered to without the use on any Message Rules.

Outlook can still be configured this way today without losing the indication by which account you received a message with. In older versions of Outlook, all emails from all POP3 accounts used to be delivered to a single pst-file which created a Unified Inbox. When you configure multiple POP3 accounts in Outlook, all the emails will be delivered to their own dedicated pst-file.