We are running exchange 2010 and for some strange reason about every 4 to 6 months I have about 15 to 20 users accounts are disabled. They get the message when logging into their web mail that their account is disabled. I then go to exchange management console and look under disconnected mailbox and i see these
account listed here. I disable their accounts and once i do that i can go back to disconnected mailbox and find their accounts and reconnect it to that user and everything is fine again until this happens again in about 4 to 6 months.