Any assistance would be great! Here is the problem, last week we made some changes to our spam filters to increase the block rate, due to an influx of zip-file containing spams from postmaster. A few days later, we upgraded the spam filter to the latest version. All works well, with one exception. Delivery reports on emails sent inside AND outside (mixed recipients) no longer come through. To explain: User generates email, with a request for delivery confirmation... 1) Email sent to XXX@myserver.local (using exchange internal email), with delivery confirmation; delivery confirmation received by sender 2) Email sent to XXX@otherserver.net (using exchange/smtp), with delivery confirmation; delivery confirmation received by sender 3) Email sent to XXX@myserver.local, and XXX@otherserver.net (using exchange/smtp), with delivery confirmation; no delivery confirmation is received. No messages in the spam filters, no messages in the exchange logs. Anyone able to offer a hand in a solution? It doesn't look like the GFI spam filter, since half of the message should be generated below the GFI spam filter (internal delivery confirmation) even if the external portion was being blocked (which I can't see evidence of) Server 2003 SBS w/ Exchange 2003, GFI MailEssentials (latest as of 09/04/12)