A problem I've been having more and more frequently is that I'll get a piece of spam in my POP3 account which Outlook is unable to process. This causes Outlook to keep downloading the same messages over and over from the server and it's unable to grab the latest messages.
Fortunately I found a nice little freeware utility years ago called Vallen POP3 Mail Checker that allows you to connect to a POP account and remove delete messages setting in your spool. This little utility works really great and doesn't require any installation—you can just unzip the exe into a folder and run the pop3.exe.
This little utility is also great for checking other miscellaneous POP3 accounts. I use it to occasionally connect to account that are set up for automation, so I can delete a message if it's causing problems with the server.
Anyway, since I just had to run this program again to delete some spam from my mail server, I thought I'd post about this great little tool.