When using the CLI utility nvremovemedia to delete a particular media, the utility does not found the media in question, however the medialabel is indeed valid and exists.
[root@cup util]# ./nvremovemedia -medialabel "M009 (M009)"
Media 'M009 (M009)' not found
[root@cup util]# ./nvremovemedia -medialabel "M005"
Media 'M005' not found
Using "nvremovemedia -displaymedialist" which lists all media doesn't return any result:
[root@cup util]# ./nvremovemedia -displaymedialist
However using "nvmediadetails -group monday -listlabels" which is another way of getting the media list shows the tapes we are looking for:
M005 (M005) 100% used
M009 (M009) 4% used 376.89 Gbytes left
Under the current version of NVBU (8.5.3), there is a defect with the nvremovemedia utility whereby it would exit prematurely when it encounters an empty group node. If there is a group with no tapes under, nvremovemedia would finish its scan when it encounters such empty group node.
As nvremovemedia exits prematurely on encountering an empty group (without media), removing this group should help.
Go to NVGUI > Media Management > identify any empty group > right click the empty groups > Remove Group.
Note that in some cases restarting NVBU might automatically recreate groups that had been created under SmartDisk.