For some reason, we suspect all users have "Enable Delivery Confirmation" for Internet email selected. This appears to of happened after we changed a setting on the client options at the domain level. We changed the Archie UNC path, so you'd hope it never changed anything else.
But since doing this, lots of people are getting delivery notifications for their external email.

But the "Enable Delivery Confirmation" setting is not something you appear to be able to select for the users, without doing it from each persons client?

Can anybody help?

Thanks, Alan