BACKUP failed to complete the command BACKUP LOG is a common SQL Server error message. In large IT departments a member of the Operations Team logs the call to a DBA queue.

An example message is

The 09.30 log backup also failed checked sqllog - 28-06-2011 09:30:22 Backup of DatabaseUsers failed. ACO5422E Received the following from the MS SQL server: An exception occurred while executing a Transact-SQL statement or batch. BACKUP LOG cannot be performed because there is no current database backup. BACKUP LOG is terminating abnormally.

Step 1 – Go to the SQL Server Logs and find the message.

Step 2 – Investigate database configuration changes

If you observe a sequence of events , such as RECOVERY to SIMPLE followed by a RECOVERY to FULL , then it’s a candidate for the root cause of the error message

When a SQL Server database - has a LOG BACKUP schedule, and the Recovery Model changes from FULL to SIMPLE, then upon changing back to FULL – and FULL BACKUP must occur to start a new log backup chain

If you can’t see these messages – consider investigating other causes.A similar problem is Copy only backup in SQL server 2005 and not break the backup chain

Step 3 – Request from Operations or a SQL Server DBA to take a manual FULL BACKUP of the database.

This should allow the next request for a LOG BACKUP to complete successfully.

Republished from http://www.sqlserver-dba.com.