About cached names for virtual machine backup
The NetBackup policy maintains a cache file of virtual machine names. The names are shown in the Browse for Virtual Machines dialog box. You can select a virtual machine from the cached list in the dialog box, rather than waiting to rediscover them on the network. This approach can save time if your site has a large number of virtual machines.
If you change the VM display name in the Hyper-V Manager, the new name may not be used for backups until the cache is renewed. On the policy's Browse for Virtual Machines dialog box, click the refresh icon to the right of the field to update the list of virtual machines.
See Creating a Hyper-V policy from the NetBackup Policies utility.