Veeam Backup Fails: VSS Writer Errror 0x800423f4 (Azure AD Connect) – New 31/10/2017

This is an updated post about the issue with Veeam backup failures. The original post is here.

This can be fixed by using the following script and using it as a pre-script before backup.

Script

stop-service -displayname "Microsoft Azure AD Sync"
$FQlogonaccount = Get-WmiObject -Class Win32_Service | ? { $_.displayname -match "Microsoft Azure AD Sync"} | select Startname
$split = $FQlogonaccount.startname.Split("\"[0])
$username = $split[1]
$sqlprocess = Get-WmiObject -Query "Select * from Win32_Process where name = 'sqlservr.exe'" | Select Name, Handle, @{Label='Owner';Expression={$_.GetOwner().User}} | ? { $_.owner -match $username} | select handle | Out-String
$sqlpid= $sqlprocess.Split("`n")[3]
Stop-Process -id $sqlpid -force
start-process -filepath "MsiExec.exe" -argumentlist "/f {6C026A91-640F-4A23-8B68-05D589CC6F18}" -wait
Start-Service -displayname "Microsoft Azure AD Sync"

Steps

  1. Save the script as ps1 file. Put somewhere in the Veeam server.
  2. Right-click the backup task and choose “Edit”
  3. Choose “Guest Processing” -> “Enable application-aware processing” -> “Applications”
  4. Choose the one VM that have AAD tool installed and click “Edit”
  5. Go to “scripts” -> “Require successful script execution”, then locate the script we just created.
  6. Now you’re done.

Veeam Backup Fails: VSS Writer Errror 0x800423f4 (Azure AD Connect)

An updated post is here 31/10/2017

Hi Guys.

An interesting issue over the last few days. Our backup logs have had the following failures in Veeam.

Unable to release guest. Error: Unfreeze error (over VIX): [Backup job failed. Cannot create a shadow copy of the volumes containing writer's data. A VSS critical writer has failed. Writer name: [SqlServerWriter]. Class ID: [{a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}]. Instance ID: [{6323fe10-0205-47df-b015-4a5ff60c31e2}]. Writer's state: [VSS_WS_FAILED_AT_PREPARE_SNAPSHOT]. Error code: [0x800423f4].]
Error: Unfreeze error (over VIX): [Backup job failed. Cannot create a shadow copy of the volumes containing writer's data. A VSS critical writer has failed. Writer name: [SqlServerWriter]. Class ID: [{a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}]. Instance ID: [{6323fe10-0205-47df-b015-4a5ff60c31e2}]. Writer's state: [VSS_WS_FAILED_AT_PREPARE_SNAPSHOT]. Error code: [0x800423f4].]

Digging through the event logs, you will see errors like the following:

  1. Inital backup
    SQLVDI: Loc=SignalAbort. Desc=Client initiates abort. ErrorCode=(0). Process=19908. Thread=18488. Client. Instance=LOCALDB#SH7A2278. VD=Global\{C7140958-2759-4979-BA55-0E3F258064ED}1_SQLVDIMemoryName_0.

    vpxclient_2016-09-08_13-09-55

  2. Followed by
    A VSS writer has rejected an event with error 0x800423f4, The writer experienced a non-transient error. If the backup process is retried,
    the error is likely to reoccur.
    . Changes that the writer made to the writer components while handling the event will not be available to the requester. Check the event log for related events from the application hosting the VSS writer. 
    
    Operation:
     PrepareForSnapshot Event
    
    Context:
     Execution Context: Writer
     Writer Class Id: {a65faa63-5ea8-4ebc-9dbd-a0c4db26912a}
     Writer Name: SqlServerWriter
     Writer Instance Name: SQL Server Code-Named 'Denali' CTP2:SQLWriter
     Writer Instance ID: {2f97c809-8eb4-431c-93ac-b0f81e610013}
     Command Line: "C:\Program Files\Microsoft SQL Server\90\Shared\sqlwriter.exe"
     Process ID: 19908

    mstsc_2016-09-08_13-17-47

    mstsc_2016-09-08_13-18-02

We have found this issue is related to an update of the Microsoft Azure AD Connect client.

On all servers that were affected by this, we had just upgraded to the latest Azure AD Connect client. This seems to corrupt the SQL writer somehow.

We haven’t seen many reports of this. There are various fixes for the 0x800423f4 error, but the easiest fix is to repair the LocalDB SQL instance.

To do this:

  1. Go to Add/Remove Programs
  2. Select Microsoft SQL Server 2012 Express LocalDB
  3. Select Repair
    vpxclient_2016-09-08_13-11-17

Once this is finished, you will need to reboot.

We had this issue with many servers. This process fixed it on everyone.