Collected SQL Server transaction logs do not match any existing database backup: SQLINSTANCE\DATABASE

This error occurs because the collected transaction logs do not match the existing backup of the server. The most common cause is that a SQL-level database backup or transaction backup has occurred that was not triggered by the Veeam SQL Server Transaction Log Backup job.

Note: Native SQL Backups cannot be taken in conjunction with Veeam's SQL Server Transaction Log Backup unless they are COPY ONLY. Other applications interacting with the Transaction logs will break the consistency of SQL Server Transaction Log Backup and cause the error documented in this article.

To resolve this issue, run the associated backup job to create a new restore point for the SQL server failing to be processed by the SQL Server Transaction Log Backup job.

For more information about how the SQL Server Transaction Log Backup works, review: How Microsoft SQL Server Log Backup Works

The SQL Server Transaction Log Backup can be toggled between running states by disabling the associated backup job. When the job is disabled, the SQL Server Transaction Log Backup will stop.

If running the backup job causes the error to stop occurring, and the error returns in the future, review the scheduled tasks on the SQL server with your Database Administrator to ensure no other software interacts with the SQL Transaction Logs other than Veeam.