At our office we use one shared office email address and are receiving e-mails to 10 locations via Outlook 2007. The last few months email are not showing up on on every desktop (for many years they did). I have reconfirmed they all have "leave a copy of messages on server" checked.
We are not against upgrading versions but it's a large expenditure and we would only do that if we were sure that solves the problem.
Separating the emails (one per station) is not a viable option since everyone check the general email box.