Examkin

Question

Difficulty: HardTroubleshooting Windows OS Startup and Boot Errors

A desktop computer running Windows 10 on a legacy Master Boot Record (MBR) partitioned system drive fails to start following a sudden power outage. Immediately after the Power-On Self-Test (POST), the system halts and displays a black screen with the message 'Invalid partition table'. The hard drive is correctly identified in the system Firmware/BIOS settings, but the operating system fails to initialize. A technician boots the machine using Windows 10 installation media and opens the Command Prompt within the Windows Recovery Environment (WinRE). Which of the following commands should the technician execute to repair the master boot code and rewrite the partition boot sector? (Select TWO.)

  1. bootrec /fixmbrAnswer
  2. bootrec /fixbootAnswer
  3. C
    bootrec /rebuildbcd
  4. D
    sfc /scannow /offbootdir=c:\ /offwindir=c:\windows

Answer

The technician should execute 'bootrec /fixmbr' and 'bootrec /fixboot' to repair the Master Boot Record and write a clean boot sector to the system partition.
The 'Invalid partition table' error at POST indicates corrupt bootloader instructions in the Master Boot Record or volume boot sector on legacy MBR disks. Running 'bootrec /fixmbr' repairs the master boot code, and running 'bootrec /fixboot' writes a compliant volume boot sector to ensure the OS bootloader can start.

Step-by-Step Solution

1
Diagnose the boot failure stage and error message.
The 'Invalid partition table' error occurring immediately after POST on an MBR disk indicates corrupt boot code in the Master Boot Record or damaged volume boot sector code.
Identifying that the error occurs prior to OS initialization isolates the issue to low-level disk boot structures rather than system files or BCD entries.
2
Execute 'bootrec /fixmbr' in the WinRE Command Prompt.
The Master Boot Record is updated with valid master boot code compatible with Windows 10.
This repairs damaged or missing MBR code caused by power loss without disrupting the partition entries.
3
Execute 'bootrec /fixboot' in the WinRE Command Prompt.
A fresh boot sector compatible with the system partition is written.
This ensures the volume boot code can properly locate and initiate the Windows Boot Manager (BOOTMGR).

Key Concept

Legacy MBR and Boot Sector Repair via WinRE Bootrec
Rate this question

Topics

Troubleshooting Windows OS Startup and Boot Errors

More questions from this topic