2830 Unique secondary index must be dropped before restoring table.
During a single-AMP restore of a nonfallback table, the table header on disk indicated the existence of a unique secondary index.
Because a single-AMP restore should always be preceded by an all-AMPs restore with the single AMP down, and because the unique secondary indexes on a nonfallback table are invalidated during such a restore, this error indicates a user error. Either the index was added after the AMP came back up (modifications should never be made to the database until the AMP is restored), the single-AMP restore was not preceded by an all-AMPs restore, or the single-AMP restore was not preceded by an all-AMPs restore.
The restore operation must be started over.