I was looking into a missing mail message for a user, and saw one of the messages had an eventid of "HAREDIRECTFAIL".
Expanding my search, I see the log flooded with these. I am fearful some of these messages were not delivered.
There is a single Exchange 2013 server. All mailboxes were migrated from an Exchange 2010 server, which has since been decommissioned and removed.
Could these eventid's be related to the decommissioned Exchange 2010 server? Are they a concern?