If the Master Boot Record (MBR) is corrupted or damaged then Windows Boot Manager failing of boot error message occurs. The cause of this error is a virus or malware infection and in case you turn off your system abruptly. Thus, below are the steps to fix this error quickly:
1) Click on the F8 button when the system is booting to visit the Windows Recovery option.
2) Tap on the Troubleshoot→ Select Advanced Options.
3) Then use this Bootrec.exe tool→ Press Command Prompt
4) Type in the below given command one by one and use the Enter key when you attempt each.
A) bootrec /RebuildBcd
B) bootrec /fixMbr
C) bootrec /fixboot
D) bootsect /nt60 SYS or bootsect /nt60 ALL
5) Exit this operation now. Lastly, reboot your system.