When you try to restore your important data from a Microsoft Windows backup file (BKF file) with the help of NTBackup.exe utility, you might encounter the below given error message:

“Unable to Restore”

After this error message, the NTBackup tool refuses to work and the restoration process gets halted.

Cause

This problem could take place if NTBackup.exe tool encounters any unknown data stream in the BKF file. An unknown data stream could be caused by the third party BKF file, which holds the data streams with Stream ID’s that aren’t known by NTBackup.exe utility. Instead of passing over the invalid streams and proceeding with restoration procedure, NTBackup.exe becomes incapable to restore the data and shows you the error message.This problem can also occur due to corruption to the BKF file because of invalid data streams. After corruption, NTBackup tool can not read the data from BKF file and thus could not restore it.

Resolution

To solve out this problem, you need to install the latest service pack of Microsoft Windows operating system version you have installed. This hotfix allows NTBackup to skip unknown data streams and thus it continues to restore the data.

Although, the hotfix is able to avoid the problem in future, but it can not repair the corrupted BKF file. To fix this problem, you need to carry out bkf repair.
BKF repair is feasible with the application of third party BKF File Repair tools, known as MS backup Recovery software. These Microsoft Backup File Repair software are capable of methodically scanning the corrupted BKF file and extracting all of the data from it.

Stellar Phoenix BKF Recovery software is the most comprehensive and commanding product with high scanning abilities. This software works in most of the BKF corruption scenarios and gives you fruitful BKF File Repair results. It works well with BKF files created by Windows 2000, XP, and 2003 NTBackup tool.