I've recently been working on exporting VMs from a single Hyper-V server and importing them into a Hyper-V Failover Cluster. While running the import I kept running into a general permission denied error.
Searching didn't turn up a solution, and posting about it only led to work-arounds, but no solution (given what I discovered, the work-arounds would have had the same problem).
A MS Failover Cluster with Cluster Shared Storage has one machine/node that is the 'owner' of the storage. When you perform the import, you MUST perform the import on the machine/node that is the 'owner' of the Cluster Shared Storage.