Hi @Tore ML please find the reference for tail-log backup, you will find this option from advanced options
https://documentation.commvault.com/v11/expert/61510_advanced_backup_options_data.html
 

Tail Log Backup (on a Damaged Database)

Available only for a transaction log backup.

Backs up tail of the log to capture the log records that have not yet been backed up. A tail log backup recovers a database to the point-of-failure. If you do not select this option, you can recover a database only to the end of the last backup that was created before the failure.

For example, if a database was damaged or a data file was deleted, start a tail log backup before attempting a file or filegroup restore operation. After the log tail is backed up, the database is left in the RESTORING state.

Before starting the tail log backup, verify that the SQL Server database is set to a full or a bulk-logged recovery model.