I have a client who is running Exchange 2000 on a single server. They are getting a lot of spam and are working through that with their spam solution provider (3rd party hosted solution), but right now we want to disable the NDRs to help control the flow of traffic. We have disabled the "Allow delivery of failure reports" in System Manager and have rebooted, but the NDRs are continuing to be generated (Message tracking shows no effect based on the NDR option). Since this has started (and I assume it is because of the traffic), the users are unable to open/view any messages that have attachments, regardless of size. This problem is experienced in both Outlook and OWA. Normal messages without attachments come through fine and are viewable, also regardless of size. I have absolutely no idea about the attachment issue, and am curious if there is another way to disable NDRs manually, other than the option that currently is not working. I would really appreciate any help on this. Thanks!

Some more information: When users attempt to open a message with an attachment in outlook, a pop-up appears that simply says "Can't Open item". If users try to view a message with an attachment in OWA, the page errors out with a general HTTP error that the page cannot be found. This is happening with both Outlook 2003 and Outlook 2007 clients, and OWA 2000. This is happening for all users. Creating a brand new mail profile on a machine will experience this issue immediately. If users use "cached Exchange mode", they receive lots of errors in the Sync Failures folder. Here is a copy of one (they all have the same error code): 20:39:22 Synchronizer Version 11.0.8200 20:39:22 Synchronizing Mailbox 'USER' 20:39:22 Synchronizing Hierarchy 20:39:22 Synchronizing server changes in folder 'Sent Items' 20:39:22 Downloading from server 'exchsvr01.domain.com' 20:39:22 Error synchronizing folder 20:39:22 [80004005-501-C0090081-560] 20:39:22 The client operation failed. 20:39:22 Microsoft Exchange Server Information Store 20:39:22 For more information on this failure, click the URL below: 20:39:22 http://www.microsoft.com/support/prodredirect/outlook2000_us.asp?err=80004005-501-c0090081-560 20:39:22 Done The URL doesn't exist and deals with outlook 2000 anyway. Any ideas? Thanks!

I have fixed the attachments problem. They use Symantec mail Security for Exchange and the service had been stopped and would not run. Once I fixed that and the service started, the attachment messages and OWA views worked correctly. Score one for Symantec, it must be an automatic setting to disable the attachment viewing until it can be scanned. Pretty good security measure. As for the NDRs, I am still curious as to why unchecking that box has no effect. thanks! Brandon