For the past few months I’ve been using an in house script to manage the rebooting of Virtual Machines on Hyper-V hosts following Windows Updates. These Virtual Machines also take part in Hyper-V Replica Replication to a DR host. On occasion I’ve spotted that when shutting down (as part of the reboot sequence) the Hyper-V Replica state will go into a Error ‘Critical’ state.
As it transpires this happens when the machine is shutting down and Hyper-V replica is attempting to create a reference point to send replica data over to the DR host.
The best fix I have at the moment for this issue is to suspend replication (you can use the Suspend-VMReplication PowerShell Cmdlet as documented here – https://technet.microsoft.com/en-us/itpro/powershell/windows/hyper-v/suspend-vmreplication to accomplish this) before shutting down the machine and then resuming replication (Resume-VMReplication and https://technet.microsoft.com/en-us/itpro/powershell/windows/hyper-v/resume-vmreplication) once shutdown is complete.
You will also note this issue noted under Hyper-V-VMMS in Event Viewer with Event IDs along the lines of 19060, 33680, 32546 and 32026.
Well, this just happened to me and you explained how to avoid this, but you did not explain what you did to “clean up” the critical error. Even though I perform backups regularly on the primary VM’s, I am always paranoid making a mistake with production VM’s.