The said message indicates that there aren't valid restore points that should be copied by backup to tape job. Sometimes you might get this message when incremental processing option is enabled
. As far as I remember, some of these issues have been fixed in the recent patch, so, if you haven't it done already, it might be worth upgrading now.
Also, you can open a ticket with our support team and let them confirm your environment.
I haven't try to backup file to tape what is the difference ? There is a difference for restore if I use file-to-tape ?
The difference is what is playing the role of job "source". Backup to tape job operates with backup restore points, meanwhile, file to tape job with files.
Another difference between the job types is availability of tracking mechanism of backups and restore points. With "backup to tape" jobs you will know on which tape medias particular VMs reside on, what medias are required in order to restore certain VM, etc. In case of file to tape job, you should go to the "Files" tab, find required file or directory and restore it.