I have a few users who are constantly being hit with the Outlook Mailbox Cleanup box. This always happens to them when they are out of the office and it is always next to impossible to get them to a point where they are able to send e-mails again because this message just stops them cold. We've opened them up in Exchange as much as we possibly can and we have given them the never ending speech about keeping their mailboxes as small as possible, but does anyone know of a way to prevent the Mailbox Cleanup box from coming up at all? Is this a registry setting that I'm just not finding? Please HELP!!!