Backup files are generally created with ntbackup.exe utility in Windows. They help you to restore data after upgrading or clean install and most importantly during data loss. However, BKF files can itself get corrupted due to interruption during backup, CRC (Cyclic Redundancy Check) errors, virus attacks, sudden system shutdown, and other reasons. Use Kernel for BKF repair software to restore all data and get rid of permanent data loss fears.