How to resolve Event id 18400 after install Veeam 9.5 Update 3

Backup Server it's not need lot of troubleshooting but when a problem arise must be resolved as soon as possible.

The reason is that you don't want to failed or your backups for one day. NEVER you don't know when you will request to restore a backup file or a full VM.

Another reason is that you don't know want to expose in your Manager or CEO that failed to restore files from previous day that somebody needs.

Today i would like to give you the solution of an issue that maybe face after update Veeam 9.5 Update 3.

What was the problem.

As every morning the first job is to check my Backups Status.

In my email i receive a notification for failed backups of specific Servers.

I login in Backup Server and i open the Failed Job from Veeam to see what happened.

The error was new and i didn't see it again.

Microsoft SQL Server hosting the configuration database is currently unavailable ..................
Unable to apply retention policy ....................


  • First thought. Of course to search in Google.
  • I found lot of same issues from other IT and the problem was start after install the Update 3
  • So to get in more details i open the Event Viewer of Windows Server and i see lot of errors wit Id 18400 related with Sql Server.


  • What was the problem
  • After few minutes while search i found an article from Veeam that this is problem after installation of Update 3 and the cause is  that the SQL logs are not truncated during backup, but the truncation task is still marked as a success in the job statistics. 
  • Of course the only thing that was interesting it was how to resolve it.
  • So to resolve this error first of all you must download and install the Sql Server Management Studio 18 to have access in the Databases if you don't have it install.
  • After install open the Sql Server Management Studio 18 and login with the user base on the configuration that you have done in the Veeam installation.


  • If you don't have use Sql Server before you will find the article of Veeam difficult.
  • Click on logins and select the user that use for Guest Processing. What it does mean? To understand exactly which user must configure right click in one backup job of Veeam and select Edit. Go in Guest Processing and find the user that use. Most of the times this use it in Domain Controllers or Exchange Servers for Application Aware processing.


  • So when you find the user return in Sql Server Manager , in Logins and double click in the user.


  • Click in Server Roles and check the dbcreator and public.


  • Click in User Mapping. Select the VeeamBackup database and check the db_backupoperator, db_denydatareader, public


  • Select the master database and check the  db_backupoperator, db_datareader, public


  • Select the msdb database and check the db_backupoperator, db_datawriter, db_datareader, public



  • Click in Securables. Go in the bottom and check the view any definition, view server state.



  • As per Veeam documentation if you have SQL Server 2012 or SQL Server 2014 database transaction logs, this account should have the db_backupoperator database role (minimal required) or the sysadmin server role.

After these changes i start again the Backup Jobs and all works fine.

Have a nice weekend !!!!

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