i had a fine working Exchange GRT Backup to Disk. Everything worked even single mail restore.
Now imagine what happened during the copy to tape ?
Yes, "Access Denied"
or more detailed:
V-79-57344-33928 - Access is denied. Access denied to directory .
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.
Exchange 2007 is on W2KR2 installed.
Media Server BE2010 is on W2K8R2 installed.
Solution was to implement the ipv6 workaround mentioned in
It looks like, as if the media server wants to talk itself with the ipv6 address, which just did not work.
But it works with ipv4.
I hope this information helps other people in their troubleshooting.