I run multiple POP mailboxes, and have the 'Leave copy of messages on server' set for 20 days. I have been working like this for several years. However, I have just this week upgraded to Outlook 2010, and for some reason a couple of the mailboxes are downloading all the messages again, each time I open outlook. I have gone through all the settings but I can't see anything obvious, and apart from the upgrade to 2010, I havent touched any settings (2010 imported everything from 2007). I use webmail when away from my PC, hence why I leave a copy of emails on the server. Any ideas? It only downloads when Outlook first opens, thankfully not every time I do a send/receive.