Hi Larry,
Very strange as we do not use encryption on the tapes to the best of my knowledge. It's also strange as it'll cat some tapes but not others! I have another full backup set to try on a fresh tape that isn't 100% full to see if it plays ball then,
It is a standalone IBM LTO4, rebranded as a Dell Powervault. We're using LTO4 media.
We can Cat/restore in our live environment which is a RoboLib but again uses an IBM lto4 tape drive at the end of the day. I would like to think if the building burned to the ground, we wouldn't need an exact match on hardware to beable to simply catalog a tape.