When backing up the virtual machines that reside on the same CSV, Windows warning 1584 can be ignored
In a simultaneous backup of virtual machines that reside on the same Cluster Shared Volume (CSV), the following Windows warning event (1584) may be issued:
A backup application initiated a VSS snapshot on Cluster Shared Volume Volume1 (Cluster Disk 8) without properly preparing the volume for snapshot. This snapshot may be invalid and the backup may not be usable for restore operations. Please contact your backup application vendor to verify compatibility with Cluster Shared Volumes.
For this case, Microsoft has acknowledged that message 1584 is a false alarm. For NetBackup backups of the virtual machines that reside on the same CSV, this warning can be safely ignored.