http://www.outlook-tips.net/howto/grouping.htm

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Milly Staples [MVP - Outlook]
Post all replies to the group to keep the discussion intact. All
unsolicited mail sent to my personal account will be deleted without
reading.
After furious head scratching, Stephen asked:
| Outlook 2003 has a default setting to arrange email in folders by
| groups, and has to be manually turned off for each folder. Please
[quoted text clipped - 7 lines]
| button, follow this link to open the suggestion in the Microsoft
| Web-based Newsreader and then click "I Agree" in the message pane.
http://www.microsoft.com/office/community/en-us/default.mspx?mid=e85cde7b-0dd5-4
6f8-964b-6235b8ef03a8&dg=microsoft.public.outlook.installation