8 Krypton

Re: How to delete a DataDomain storage system in NetWorker 8.2.3.

It seems to be related somehow to integration with VC - not sure if there is some extra dependency as I do not run such setup.  Best bet is to open a ticket with support.  Not sure if you could remove it by forcing it with nsradmin (for example, while NSR is down), but you may try that as well.