Oracle Error Message
ORA-19660: some files in the backup set could not be verified
Reason for the Error
A restore conversation was made to verify all the files in a backup set, and the files which were printed in messages 19661 or 19662 could not be verified because corrupt blocks for those files were found in the backup set.
Solution
Unless the damage to the backup set can be repaired, the indicated files cannot be restored from this backup set.