How do I... Archive Outlook e-mail without a PST file?

Within those subfolders, create monthly or quarterly folders within which you place copies (just drag-and-drop them en masse) of every e-mail message you store within Microsoft Outlook. You can also create folders for Sent Mail and, if you're truly into backing up all your e-mail, Deleted Items as well.

Once you've copied messages to the Email folder, you can delete them from Outlook. Thus you receive an added benefit. Outlook will open and operate more smoothly and consistently, as you'll be working with a much smaller PST file (which will power only active e-mail messages, tasks, contacts and calendar items that haven't been copied to the Email folder and deleted from Outlook). Plus, maintaining a small PST file will keep you out of trouble with the Exchange administrator (who likely implements and maintains strict mailbox size limits).