Unable to restore data - The media identifier does not represent a valid medium

Hi there,

We're using BUE 2014 SP2.  CAS server and two MMS servers.  Backups run to MMS server A and duplicate to MMS server B.  I can restore data from MMS server A but not from MMS server B.  The error returned is:

The media identifier does not represent a valid medium

So whilst I can get my data from the first server, the second server is my DR site - so I need to be able to recover the data from this box.

Any help will be gretly appreciated.

Thanks,

Danny