Just wanted to let you know a recent problem and fix I was having recently.
Server 2016, Hyper-V hosts, Clustered, iSCSi storage
Disk Manager would hang when I would open it. Also, I couldn't "connect" to any VM via Failover Cluster Manager nor Hyper-V Manager. If I would reboot both nodes in the 2-node cluster, it would work as expected for a short time. I have 8 of these 2-node clusters. It was happening on all 8 clusters.
After working with MS support, we were able to determine that it was coming from our Avocet IP KVM. The Avocet have Virtual Disk capabilities (basically, it has the option to mount a disk via the USB port through the KVM). There was a recursive call in the Virtual Disk Service for this VD. I was able to disable the VD via the KVM management console to fix the problem.