220-1102 Question 44
Single answerMaster boot record (MBR)A technician is repairing a Windows 10 desktop that was previously working normally. After a sudden power loss, the system no longer starts and displays an error indicating the operating system cannot be found. The PC uses Legacy BIOS mode and the system drive is configured with an MBR partition style. Startup Repair does not resolve the problem, but the drive is detected correctly in firmware settings. Which action should the technician take NEXT to repair the boot process with the LEAST disruption to user data?
- A
Boot to Windows Recovery Environment and run bootrec /fixmbr
- B
Convert the system disk from MBR to GPT using diskpart clean and convert gpt
- C
Disable Secure Boot in firmware and reboot the system
- D
Reformat the system partition and reinstall Windows
- E
Replace the hard drive immediately because MBR corruption means the disk has physically failed
Show answer and explanation
Correct answer: A
Explanation
The master boot record is located in the first sector of an MBR-initialized disk and contains boot code plus the partition table used by BIOS-based systems to begin startup. If that boot code becomes damaged, the system may fail to locate or start Windows even though the drive is still visible in firmware. In this scenario, the least disruptive corrective action is to use the Windows Recovery Environment and run bootrec /fixmbr. This aligns with Microsoft's documented recovery tools for repairing BIOS/MBR startup problems. More invasive actions such as repartitioning, converting to GPT, or reinstalling the OS should only be considered after non-destructive boot repair steps fail. Best practice is to confirm boot mode, verify the disk is detected, attempt WinRE repair commands such as bootrec, and preserve user data whenever possible.
- A. Correct.
Correct. On a BIOS-based system using an MBR disk, corruption in the master boot record can prevent the OS from loading even when the disk is still detected. Running bootrec /fixmbr from the Windows Recovery Environment writes a new Windows-compatible MBR to the system disk without overwriting the existing partition table, making it an appropriate low-impact repair step.
- B. Incorrect.
Incorrect. Converting the disk to GPT with diskpart clean would erase partition information and destroy access to existing data unless the disk is backed up and reconfigured. In addition, GPT is typically used with UEFI systems, not as an immediate repair step for a BIOS/MBR boot failure.
- C. Incorrect.
Incorrect. Secure Boot is a UEFI feature and is not relevant to a Legacy BIOS system using MBR. A technician might choose this option if confusing UEFI boot settings with BIOS/MBR startup problems.
- D. Incorrect.
Incorrect. Reformatting and reinstalling Windows is far more disruptive than necessary and risks data loss. Since the drive is detected and the issue began after a power event, repairing the boot record is a more appropriate next step before considering destructive recovery methods.
- E. Incorrect.
Incorrect. An MBR issue does not by itself prove physical disk failure. Logical corruption of boot code can occur after improper shutdowns or interrupted writes. The technician should attempt logical boot repair first, then evaluate disk health separately if needed.