Consider the following scenario:

  • You use AlwaysOn Availability Groups in an instance of Microsoft SQL Server 2016 or 2017.

  • You set up SQL Server Managed Backups on one or more of your user databases which is added to an available group.

  • You run an on-demand log backup on the database.

  • You remove the database from the available group and then add it back. Or, you failover your database.

  • You run an on-demand log backup on the database.

In this scenario, you find there is a break in the log chain by querying the managed_backup.fn_available_backups table on the msdb database.


This issue occurs because when you remove the database from an available group and then add it back or you failover your database, a new database GUID is created in the database_guid column of the smart_backup_files table. This causes the partition to list the data in nonsequential order and triggers the break log chain.


This fix is included in the following cumulative updates for SQL Server:

Cumulative Update 1 for SQL Server 2017

Cumulative Update 5 for SQL Server 2016 Service Pack 1

About SQL Server builds

Each new build for SQL Server contains all the hotfixes and all the security fixes that were included with the previous build. We recommend that you install the latest cumulative updates for SQL Server:

Latest cumulative update for SQL Server 2017

latest build for SQL Server 2016


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.


Learn about the terminology Microsoft uses to describe software updates.

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