You don't do this everyday, so just post it here for the record.
Steps to resend bad messages:
- Stop the SMTP Service: Open IIS Manager, right-click SMTP Virtual Server, then click Stop.
- Copy all bad message files (with extension of .bad) under Badmail folder to Pickup folder
- Remove the .bad extension
- Start the SMTP service, and watch them being redelivered.
File types under Badmail folder:
- .bad: the message failed to send
- .bdp: the diagnostic message
- .bdr: the body of the (None-delivery report) NDR.
