In Hyper-V 2016 Microsoft implemented a possibility to share a virtual hard disk (in .vhdx or .vhds format only) between two or more VMs and use that virtual hard disk as shared storage when building guest clusters.
When adding a Windows Server 2016 Hyper-V cluster to the Veeam Backup & Replication Console, you must decide where to store metafiles created during the backup process of the VMs from the shared virtual hard disk (i.e. information about snapshot groups, etc.).
By default, the metafiles location is not defined, so you need to define it manually.