Marianne is 100% correct.
You can search for valid images in NetBackup Management > Catalog even if you have removed the policy/client.You can type in the policy name or client name yourself if it is not in the dropdown list.
My practice is to delete the policy (if no clients are left in it) and keep the client added to a "dummy" policy which has no schedules to run. This is not required but ends up useful to me in case I forget the client name (fickle memory!). With this setup, I just go to the Backup, Archive and Restore and choose the client from dropdown list.
Unfortunatley both Marianne and X2 are WRONG, even though technically they are correct.
Your initial message inferred using the drop down menu for restores - and unfortunately, NetBackup does not use the catalog or the images to populate this, and instead uses clients in policies. However - you can manually type the name in after seaching your catalog...
My solution is to create a policy named "deleted clients" that never runs. I also have a decommission policy with extended retention to my decommission retention ( mine is 1 year ).
Process - move from active policy to decom policy, run 1 yr backup. Move to deleted clients policy. I have started date stamping the clients as well, so I know when to remove them.
I have this all scripted
