I'm running into this issue shown in MS article 886616 turns out the mail rules on my users laptop take up 183kb space in the article it notes "The rule limit is now a customizable limit up to 256 KB per mailbox. " How do I increase this size?
I was migrating them to the exchange 2007 server, then not all of the rules activated.
http://support.microsoft.com/kb/886616Start Free Trial