Using Exchange 2007SP1RU8, Outlook 2003. Two mailbox servers and one CAS/HUB. The sender is on MBS1 and recipient is on MBS2I have a user that is getting repeated duplicate read receipts. A message was sent with the read receipt and subsequently deleted without reading by the recipient. The read receipt keeps showing up every 4-6 minutes in the original senders inbox. Something seems to be stuck in a queue but which one. The queues for the MBS1 & 2 show 0 messages. How can this be stopped?

Close Outlook on both clients and delete the .ost file and re-open Outlook to recreate the local cache. ( I suspect your Outlook clients are in cached mode - if that isnt the case, then create new Outlook profiles for each client.)If that doesnt fix it, check message tracking and verify that those messages are actually being sent.

Besides, please ensure that your outlook is at the latest version.