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Question

Difficulty: EasyTroubleshooting Windows OS Startup and Boot Errors

A desktop computer running Windows 10 fails to start and presents the message "Operating System Not Found" immediately following POST. After booting into the Command Prompt within the Windows Recovery Environment (WinRE), which TWO commands should the technician execute to repair the master boot record and rebuild the boot configuration storage file? (Select TWO.)

  1. bootrec /fixmbrAnswer
  2. bootrec /rebuildbcdAnswer
  3. C
    sfc /scannow
  4. D
    dism /online /cleanup-image /restorehealth

Answer

The technician should execute bootrec /fixmbr to write a compatible Master Boot Record and bootrec /rebuildbcd to scan and rebuild the Boot Configuration Data store.
To resolve startup boot sector and configuration errors, executing bootrec /fixmbr rewrites the master boot record code, while bootrec /rebuildbcd locates existing Windows installations and recreates the boot configuration file required for system startup.

Step-by-Step Solution

1
Identify the boot failure symptom
The error message 'Operating System Not Found' indicates missing or corrupted boot sector code or missing BCD references.
When the bootloader or MBR is missing or corrupted, the system firmware cannot locate the operating system files.
2
Execute the boot record repair command
Running bootrec /fixmbr writes a new Master Boot Record code to the system partition without altering existing partition tables.
This resolves corruption in the MBR that prevents the system from starting the boot chain.
3
Execute the boot configuration rebuild command
Running bootrec /rebuildbcd scans all connected storage drives for Windows installations and rebuilds the BCD store.
This restores the critical boot configuration file needed by Windows Boot Manager.

Key Concept

Troubleshooting Windows Boot Sector and BCD Corruption using WinRE Bootrec Utilities
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Topics

Troubleshooting Windows OS Startup and Boot Errors

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