Install Agent for Windows inside the virtual machines


You are trying to back up a Hyper-V virtual machine which has virtual disk with an ampersand (&) in file name, e.g. Docs&Users.vhdx. Backup fails with the following error:

Failed to get the disk information.


You back up Hyper-V virtual machines using Agent for Hyper-V. Agentless backup fails with error:

Disk '<...>.vhdx' is not found.


  1. You have native Hyper-V Replication set up: the VM is replicated between 2 or more Hyper-V hosts
  2. You back up the replica machine (VM2)
  3. You perform entire VM recovery from this backup into original replica machine (VM2)
  4. After recovery, the previously enabled Hyper-V VM replication is now replicating changes from VM1 inconsistently, since it assumes that VM2 (replica) has state different than the one it is after recovery.


  1. You back up a Hyper-V Gen2 VM using Agent for Windows installed inside VM;

    (!) This issue does not reproduce with agentless backup

  2. After you recover this backup as new VM via Agent for Hyper-V, restored VM does not boot properly: only black screen appears. When you check properties of the restored VM in Hyper-V, restored VM is Gen1.


Specifics of product implementation.

This article provides instruction for troubleshooting virtual machine backup failures in Acronis Cyber Backup virtualization solutions.


Follow these steps to troubleshoot virtual machine backup failures:


You try to boot Gen2 Hyper-V VM with Acronis Bootable Media

Media fails to boot with the following message:

The image's hash and certificate are not allowed (DB)

No UEFI-compatible file system was found.


Secure Boot is enabled on the VM. Secure Boot prevents boot from a Linux bootloader in the ISO file (the Linux bootloader neither signed nor certified by Microsoft).

This issue is not specific to Acronis Bootable Media. 


  1. You have Hyper-V 2019 environment with Acronis Backup Agent for Hyper-V installed
  2. Agent for Hyper-V sometimes loses assigned license and backups fail with an error similar to the following one:

    Functionality 'pcBackup' is not available. Please use the appropriate license


  1. You want to update several Hyper-V agents at once under Settings - Agents,
  2. When you select required agent machines, the following error is displayed:

More than one Agent for Hyper-V is selected. Simultaneous update of multiple Agents for Hyper-V is not possible. Please update these agents one by one.


  1. You have an UEFI virtual or physical machine with on GPT disk with 5 or more partitions on it, including service partitions.
  2. You back up this machine using Version 12 backup format
  3. You attempt to recover this backup to a new Hyper-V VM on a disk with sufficient space, but the operation fails with the following error:


After an update to Acronis Cyber Protect 15 Update 3 (Build 28035 or 28122) a Virtual Host license does not allow backup of both host and virtual machines.

If the license is assigned to the host, backup of virtual machines fails and VM details show "No license". If the license is assigned to VM(s), backup of host fails.

Protection plan creation may fail with an error similar to:

The protection plan cannot be used or updated for ‘<hostname>’ because the device does not have a license. 


1. You have a Hyper-V host with Virtual Desktop Infrastructure role;

2. You install Acronis Agent for Hyper-V;

3. When you try to create a new automatic collection, creation fails with 

Could not retrieve the virtual desktop template details for <VM_Name>


SAN policy is set to Offline All during Agent for Hyper-V installation. This change is necessary to prevent Windows from breaking the bootability of the VMs recovered and/or converted from backups by Agent for Hyper-V.


  • You are backing up a Hyper-V virtual machine in agentless mode,
  • Backup fails with the following error:

    Unexpected call result. Error code 32768

This article applies to backups of Hyper-V VMs performed by Agent for Hyper-V (agent-less)



Prior to performing the backup, make sure that the below prerequisites are met:

1. Hyper-V Integration Services must be up-to-date and running inside the virtual machine(s).


  • You are backing up Hyper-V virtual machine with the option Application-aware backup enabled.
  • Operating system of the Virtual machine is Windows Server 2022
  • Backup fails with "Internal error: Unsuccessful response code '7' of action request."

Acronis Cyber Protect Home Office and Acronis True Image has been tested and is guaranteed to work with just one virtual machine format: Parallels Desktop 14. It is supported by Mac version of Acronis True Image 2019 and later.

Backup and recovery of Parallels Desktop 14 virtual machines

One of the unique features of Acronis Cyber Protect Home Office and Acronis True Image 2019/2020/2021 for Mac is its unrivaled support of Parallels Desktop 14 virtual machines backup, as part of disk backup on a Mac host:

You are backing up virtual machines by an Agent for VMware or Hyper-V (agentless backup). Backup notifications are enabled. Notifications contain only the name of the host machine or the name of Agent for VMware (Virtual Appliance or Windows Agent) machine name in the e-mail subject and body.


  • You are using Microsoft`s Storage Spaces Direct
  • You are trying to preform an agentless backup of a Hyper-V VM
  • The backup fails with: "| error 0x9: There is not enough space in the storage area to create a shadow copy repository file or other shadow copy data."
  • Also other errors regarding VSS are to be expected.



  1. You are using Hyper-V or ESXi clusters with Virtual Appliance, and licenses for Virtual Host workload (any edition),
  2. It is not possible to assign licenses to all nodes of the cluster: when assigning the license to the host, the virtual machine loses the license and backup fails due to lack of license. If the license is assigned to a virtual machine instead, the host loses the license and cannot run backups.



  • You create backup of a machine which has Acronis Agent for Windows or Linux installed
  • You run this backup as VM (“Instant Restore” feature) and finalize it via Agent for VMware/ Hyper-V