A failed data migration during an upgrade may create a need to restore the Symantec Data Loss Prevention (DLP) database.
Data corruption may cause a DLP Admin to restore the DLP database from a cold backup.
Successful restores depend on proper backups and periodic restore tests.
DLP 15.X,16.X
To restore the DLP database refer to the procedure mentioned in the article Maintaining the DLP System.
Refer to Backing Up and Recovering on Windows for steps to recover on Windows platform.
And
Backing up and recovering on Linux for steps to recover on Linux platform.