Storage server already exists - illegal duplication

Hello,

NBU 7.6.0.1

Windows 2012 Master and Media Server

I started the 'Configure Disk Storage System' just to familiarise myself with creating an Advanced Disk disk storage

1. I chose my existing physical media server
2. After choosing 'Next' on the summary page the wizard start to create the storage server on the 'Storage Server Creation Status' page
3. I ended the wizard thinking that the process would not complete

I'm going through the wizard for real this time and choosing the same media server as I did the first time. When I get to the 'Storage Server Creation Status' page I get the following error:

Operation would cause an illegal duplication. Storage server (media server name) already exists in NetBackup

Can someone help please?

Thanks