I fully agree with Bob.
See this extract from NBU 6.5 Troubleshooting Guide:
The following is the procedure for recovering the system disk on a client workstation:
1 Reload the operating system as you normally would for a client workstation
of that type. If the root file system is lost, the best approach may be to reload the operating system on an alternate boot disk and boot from this disk. After restoring the system, restore root to its original partition. This lets you recover the root partition without risking a crash due to overwriting files being used by the operating system during the restore. The procedure is similar to that for the master server, except that recovering the NetBackup catalogs is not necessary. (See “Recovering the master server disk” on page 532.)
2 Reinstall NetBackup client software and patches.
3 Use the NetBackup Backup, Archive, and Restore interface to select and restore files.