Acronis Backup & Recovery 10 Management Server provides an easy way to deploy Agent for ESX/ESXi to every VMware ESX or ESXi server whose virtual machines you want to back up

The user under which you are trying to log in does not have Administrator rights

Click Configure -> ESX Hosts -> Add

Delete two registry keys to fix the issue

The typical reason for a VM to be missing in the backup or replication wizard (unavailable for selection) is that this VM was created by Acronis vmProtect and is in fact a replica VM. It is not possible to back up replica VMs by default, however this may be possible after additional adjustments

Fixed in Acronis Backup 11.5 (Acronis Backup & Recovery 11.5). As a workaround, revoke the license key and install the Acronis Agent in the guest OS

This has been fixed in Acronis Backup & Recovery 11

Install Agent for Windows inside the virtual machines