I have a problem with the RTM version of Outlook 2010 and multiple POP3 accounts. Each account is setup to the delivered to the same PST file (single Inbox) and uses the "Leave a copy of messages on the server" option. One account is set to delete server messages after 28 days, the other after 10 days.
The problem is Outlook keeps downloading the same messages over and over every time it Sends/Receives. If I remove all accounts so there is just one per PST, then it works fine. However, as soon as multiple accounts are told to deliver to the same PST, Outlook starts to duplicate messages.
This exact same setup worked perfectly on Outlook 2007 (and earlier). As a test, I deleted all accounts and setup a brand new PST. Everything was fine until I added another POP3 account into the same PST.
It seems that the "Leave a copy of messages on the server" option is broken if you have multiple POP3 accounts using the same PST. Since that is now the default option, I find it hard to believe no one has noticed this. Any ideas?