Microsoft Azure Backup Server: System State backup fails with the message replica is inconsistent

8:00 pm in Azure, Azure Backup, Cloud, IaaS, Microsoft Azure Backup Server, PowerShell, Public Cloud, Windows Server Backup by Wim Matthyssen

Last week I was setting up a Microsoft Azure Backup Server (MABS) for a customer running on an Azure IaaS v1 VM for taking disk and System State backups which are stored in an Azure Backup vault for long-term retention. After done all of the configuration, like deploying the agents and creating the Protection Group(s), most of the backup jobs ran without any issues, only the System State backups were failing. This is shown in the screenshot below.


For those who not know, I will first list some extra information to clarify what a System State backup really is:

  • A System State backup uses the Windows Server Backup (WSB) feature to take a snapshot of the system state and saves it locally to the server before moving it to the MABS server storage pool
  • It contains the following system components: System Registry, SYSVOL directory, Boot files including the system files, Active Directory, COM + Class Registration Database, Certificate Services, Cluster service information, IIS Metadirectory and System files that are under Windows File Protection (some of these items are only included if the specified service is installed – AD, ISS, Certificates)
  • §System state backup and restore operations include all system state data: you cannot choose to backup or restore individual components due to dependencies among the system state components. However, you can restore system state data to an alternate location in which only the registry files, Sysvol directory files, and system boot files are restored.

Troubleshooting a System State backup failure can be frustrating as there are a lot of underlying components that come into play during the process. To figure out what was causing the System State backup(s) to fail, I followed the steps below:

1) Check out the Critical alerts for a specific server having the issue in the Monitoring pane on the MABS server. Here I found the following error:


2) After reading the description carefully, you can see there should be enough free space on the target server and also WSB should be installed. So to verify,  first logon to the specific server trough RDP

3) Check out the free disk space by opening Disk Management


4) Like you can see, there is plenty enough of free disk space to store a local System State backup


5) To check if WSB is installed, run following cmdlet in PowerShell (as an Administrator)


6) Like you can see WSB is not installed and probably causing the failure of the System State backup

7) Install WSB trough PowerShell (as an Administrator)



8) Check if this fixes the issue by opening the Microsft Azure Backup MMC on to the MABS server. Go to Protection and select Perform consistency check …


9) Click Yes to perform the consistency check


10) You will see the Protection Status changing to “Replica is inconsistent, verification in progress”


11) To be sure everything is working like it should, you can logon to the specific server and open WSB locally by opening the Run box and typing wbadmin.msc


12) Select Local Backup. If all is running fine, their should be a local backup job running at the moment


13) After a while the job should complete Successful


14) You should also verify the successful System State backup in the MABS console. Like you can see the Protection Status of the job is OK now (also for all other System State jobs, after WSB was installed locally on all those servers)


This concludes this blog post, hope it helps!

Wim Matthyssen (@wmatthyssen)