Hi guys,
Thank you for your feedback.
I opened a support request and just get an answer. It is the encryption of the tape drives that brings the problem with. It is a known problem of DP9.05 and you have to open a case to get a fix, because there is still no fix available at the moment!
We don't touch the OS, it is still Win2k8R2SP1x64, and both, Library and Tapes are supported by DP, using this hardware since, I guess 2012.
Thanks for your help, now I have to wait for a fix from the lab .. (Jeopardy Theme)
Best regards,
Tobias