If you use Always On availability group (AG) and the transaction rate is very low (for example, less than 1 transaction per 10 seconds), you may see the following message in the SQL Server error log:

DateTime SpidId Always On Availability Groups transport has detected a missing log block for availability database "DatabaseName". LSN of last applied log block is (BlockId). Log scan will be restarted to fix the issue. This is an informational message only. No user action is required.


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


This issue is fixed in the following cumulative updates for SQL Server:

About cumulative updates for SQL Server:

Each new cumulative update for SQL Server contains all the hotfixes and all the security fixes that were included with the previous cumulative update. Check out the latest cumulative updates for SQL Server:


Learn about the terminology that Microsoft uses to describe software updates.

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