How to get Outlook 2007 to remember the option "Show an envelope in the notification area"?

How to get Outlook 2007 to remember the option "Show an envelope in the notification area"?

My question isn't like this one I don't have rules routing my messages. What happens is that Outlook will uncheck my option to show the mail icon. Not sure how or why it does this. How do I make Outlook remember or to leave alone that option?