We've recently built a new Exchange 2007 SP1 server on Server 2008 Std SP1.

We cannot do GRT backups directly to tape. We get the error "V-79-57344-766 - Cannot log on to MAPI with the specified credentials. Review the resource credentials for the job, and then run the job again." when we direct to tape.

If we run this same backup to disk it works fine. There is another Exchange 2007 SP1 server in the environment running on Server 2003 Std SP2, and that one works fine to do GRT backups direct to disk.

Backup Exec is running on a Server 2003 Std SP2 box--the installed version is 12.5 Rev 2213.

I've created a new service account for Backup Exec, and created a mailbox for it on the new Exchange server. We've loaded the MAPI/CDO agent on the Exchange 2007 server and rebooted multiple times since applying that.

The Backup Exec server account is a Domain Admin and an Exchange Full Admin. I tried assigning the Backup Exec service account to the local Administrators group on the new Exchange server and that had no effect.

Any ideas would be appreciated!