There is nothing more frustrating than having a good backup strategy only to discover, when you finally need those backups, that they are corrupted and that you cannot recover your precious data. Unfortunately this is a more common occurrence than you would expect. With NTBackup you might get a message like The Backup File Is Unusable or Unrecognized Media when you start to restore. Then the panic sets in as you realise just how valuable your data was.
The BKF format has been around for a long time and wasn't really designed to cope with the size of backups that we typically perform today. A single bit error within the BKF file renders it unusable by NTBackup which does not have any in-built capability to analyse and resolve this type of problem. The problem is exacerbated by the competitive nature of the computer hardware market. People, particularly home users, invariably opt for the lowest cost backup device without assessing the reliability of that device. Despite the highly reliable nature of hard disks, these devices can record faulty data transmitted over unreliable USB or Firewire interfaces.
How to recover the BKF Files
You have two main options when you encounter this problem. Firstly, you can appoint a data recovery agency to analyse the media on which the BKF file is stored and recover the data for you. Secondly you can purchase BKF file recovery software to analyse the BKF file and extract the good files from it. Search the internet for "BKF Recovery" using your preferred search engine. Try to find a product from a professional company that has been around for a while.