Exchange 2000 Support Pack 2 introduced a registry setting that can strip attachments from a nondelivery report (NDR) when the NDR is over a configurable size limit. Implementing this registry setting reduces the use of server resources and bandwidth when sending an NDR with attachments.
Follow these steps:
Value name: MaxDSNSize
Data type: REG_DWORD
Stripping attachments in this manner results in a couple of side effects: Exchange also strips some details from the message, along with the attachment, which prevents the NDR recipient from resending the message. This means that you must recompose the message before you can send it again. Stripping message details also prevents the NDR from displaying in Outlook's Preview Pane.
Note: Editing the registry is risky, so make sure you have a verified backup before making any changes.