I have an Exchange 2007 SP1 server with mailbox limits on the store. I have some Outlook 2007 clients that get the traditional email when their mailbox goes over the limit. On a few users with Outlook 2007, they get an annoying popup window with mailbox cleanup tools. It keeps popping up and they need to close it to work. I know its related to the mailbox limit because when I removed the limits on these users, the popup went away. My question is why do some get an email and the others a popup. I looked at all the settings I could on the client and could not find anything. The versions of Outlook are the same to the best of my knowledge.