Hello TheWaker,

What you will need to do once your backup completes is to pull out both magazines and make sure that there are no tapes that are lose in the library.  If there are no lose tapes that are not in a slot then you will want to test all the slots on the magazines with one tape to confirm that they slide in & out without too much resistance.  If you do find that that a slot or multiple slots are tight then you will want to contact support & let them know which magazine has the tight slots and they can get you a replacement if under warranty, if not under warranty then they can provide you a quote for a replacement magazine.  

Please let us know if you have any other questions.