We have installed both preconfigured appliances (ESLC and Remote Admin) for Hyper-V. We perform our backups with Altaro and got an error with both VMs because of the missing VSS support in the appliances. Altaro fortunately has a guide for installing CentOS in Hyper-V (which you can find here). According to this guide you need to install the hyper-v daemons sudo yum install -y hyperv-daemons in CentOS to Support VSS in Hyper-V. I was able to do this in the Remote Admin Appliance because I can access it via shell/root. After executing this installation I was able to perform a Altaro Backup without errors for this VM. Unfortunately I can't access the ESLC-VM via shell because of the missing access data for root. So I suggest to either provide the default root access data for the VM or to provide the package mentioned above via the update function within the appliance.