We are running Symantec Enterprise Vault 9.03 with Exchange 2003. It has been running fine for the last three years.
Recently, we upgraded to Exchange 2010 and added new targets and created new tasks. Couple of months later, the Journaling task failed then it was followed by the mail tasks that also failed with error 3305 & 2256.
After numerous days of troubleshooting and checking the online forums, I kept sseing the same discussions about VSA, permissions, Closest GC, DS Server registry entries, etc.
I verified all is set properly yet, the tasks kept failing.
I found the solution to the failing Mailbox & Journaling tasks. It appears that all of the issues we encountered last week were related to Exchange 2010 being in a DAG configuration.
The solution is to create DBs that are not part of any DAG configuration and move or create system mailboxes and place them in these DBs.
This is true for the Journaling mailbox as well.