220-1102 Operating Systems Practice Question
A technician is troubleshooting a Windows 10 workstation that fails to boot with the error 'Bootmgr is missing'. The technician has booted from a Windows 10 installation media and opened a command prompt from the recovery environment. Which built-in command-line tool should the technician use to repair the Master Boot Record (MBR) for the system partition?
⚠ Common exam trap
Test-takers frequently confuse 'Bootmgr is missing' with a BCD corruption and choose `bcdedit /rebuildbcd`, but the MBR is the first-stage boot loader that locates the boot manager, so repairing the MBR is the correct first step.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
bootrec /fixmbr
The 'Bootmgr is missing' error indicates that the Master Boot Record (MBR) or the boot sector is corrupted or missing. The `bootrec /fixmbr` command writes a new MBR to the system partition, overwriting the existing boot code without affecting the partition table, which directly repairs this issue. This is the correct built-in tool for MBR repair in the Windows Recovery Environment (WinRE).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
bootrec /fixmbr
Why this is correct
bootrec /fixmbr rewrites the master boot code to the system partition's boot sector without altering the partition table or file system. When MBR corruption prevents the BIOS from locating the bootmgr file, this command restores the standard Windows boot code that chain-loads bootmgr. It is correctly the first step in resolving a 'BOOTMGR missing' error because the boot manager cannot execute until the MBR can locate the active partition.
- ✗
sfc /scannow
Why it's wrong here
sfc /scannow verifies the integrity of protected Windows system files and replaces corrupted ones using cached copies from the Windows component store. This utility operates entirely within the installed operating system's file structure, so it cannot modify the MBR, which is physically located in the first sector of the disk before any NTFS or FAT32 file system. Even if a system file like kernel32.dll were damaged, sfc cannot run in the Windows Recovery Environment without the full system, and it would not resolve a boot failure caused by a missing bootmgr.
- ✗
chkdsk /f
Why it's wrong here
chkdsk /f inspects the file system for logical errors, file table corruption, and attempts to recover bad sectors, then repairs them when possible. It works on the volume level, scanning the NTFS or FAT32 metadata, but the MBR is a separate structure that exists outside any formatted volume. Because the MBR contains the disk signature and partition table entries, chkdsk cannot rewrite those bytes and is completely ineffective when the boot loader is missing due to MBR corruption.
- ✗
bcdedit /rebuildbcd
Why it's wrong here
bcdedit /rebuildbcd scans the system for installed Windows installations and recreates the Boot Configuration Data store, which is the database that bootmgr reads to locate the winload.exe boot loader. This command repairs missing or damaged BCD entries, but it assumes the MBR has already successfully loaded bootmgr from the active partition. If the MBR is corrupt, the system never reaches the point of reading the BCD, so running this command before fixing the MBR would fail to resolve the boot failure.
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macOS System Preferences and Settings
Key term
Windows 10
Windows 10 is a personal computer operating system developed by Microsoft that combines the familiarity of Windows 7 with the modern features of Windows 8, designed to run on a wide range of devices from desktops to tablets.
Key term
Windows
Windows is a family of operating systems developed by Microsoft that manages computer hardware and software, providing a graphical user interface for users to interact with their devices.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1102 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1102 exam.