Note: Looking for Hyper-V requirements? You can find them here.

VM Backup has the ability to coordinate with VSS to back up virtual machines in an application consistent state, but there are several conditions that must be met for this to occur.

The requirements for VMware are listed below:  

1. Firstly, check whether your VM actually requires an Application-Consistent backup. If it does not, you can disable it from the [VSS Settings] screen. Simply uncheck [Application Consistent] and Save changes. More information here.
   
   
2. If your VM is running Windows Server 2019, set the "VMware Snapshot Provider" service to "Disabled". There is currently a confirmed Microsoft bug which is preventing Application Consistent backups. More information on this here: https://kb.vmware.com/s/article/60395
   
   
3. SQL / Exchange VMs require the logs to be truncated in order to have an Application Consistent backup, so ensure that the [Truncate Logs] option is enabled for such VMs
   
   
4. The guest VM is in a running state.

    

5. The guest VM must not have any snapshots
   
   

6. The latest version of VMware Tools must be installed and running. Check and ensure that your version of VM Tools matches the latest release on the VMware Website:
   
   
   
   

7. The guest VM must be running one of the following Operating Systems:

   • Windows Server 2003

   • Windows Server 2008

   • Windows Server 2008 R2

   • Windows Server 2012

   • Windows Server 2012 R2

   • Windows Server 2016

   • Windows Server 2019

   • Windows Server 2022
     
     Desktop Operating Systems such as Windows 7/8/10, as well as non VSS-aware OS’s such as Linux / UNIX / etc, do not support Application Consistent backups, and thus the [Application Consistent] option from the [VSS Settings] screen should be disabled for such VMs.
     
     
     

8. The UUID attribute must be enabled. Might need to be entered manually in vSphere settings.
   
   

   To set disk.EnableUUID parameter from vSphere Web Client see: http://www.vnoob.com/2012/12/set-disk-enableuuid-with-vsphere-web-client/

    

   To set disk.EnableUUID parameter from vSphere Client, go to [Properties] [Options] [General] [Configuration Parameters]

    

   Otherwise, you can also check within the logs. Browse to: C:\ProgramData\Altaro\AltaroBackupProfile\Logs\OpControllers

    

   Open the relevant log file and search for the phrase: "Disk UUID not enabled"

    

9. The virtual machine must use SCSI disks only and have as many free SCSI slots as the number of disks. Application-consistent quiescing is not supported for virtual machines with IDE disks.

    

10. All the guest VM's disks have ample free space available for the internal shadow copy to complete – at least 10% free space should be available.

     

11. If the guest OS has a system reserved partition, verify that it has at least 45MB of free space. If less than that is free, ensure that a windows shadow copy can be created as per the screenshot below:
    
    
    
    

12. The guest operating system’s disks must be “Basic”, not “Dynamic”. These disks must each have at least 10% free disk space:
    
    
    
    

13. Ensure that the latest Windows Updates for the Host and VM are also applied. Please note that "Optional Updates" are usually also important for VSS operations and are suggested as well.

     

14. The “COM+ Event System”, “Distributed Transaction Coordinator”, “Remote Procedure Call (RPC)”, and “System Event Notification” services must be running within the VM. By default, these are set to “Automatic” and/or “Automatic (Delayed Start)”. The “COM+ System Application” and “Microsoft Software Shadow Copy Provider” and “Volume Shadow Copy” services must at least be set to Manual, which is the default for these. It is acceptable, but not required, to set them to “Automatic” or “Automatic (Delayed Start)”