This action is the default setting for Outlook, to track what and when you worked on the files that are stored in the Journal. This can quickly fill up your mailbox. You can also add a set of personal folders to your mailbox as an alternative to deleting messages. Select your username from the list of folders. This will allow you to save more messages within Outlook.
Personal folders act as any other folders do inside Outlook.
You can save messages there and delete them when you are ready. It will ask you if you want to add a shortcut to the Outlook Bar. This is the bar on the left hand side of the screen.