220-1102 Operating Systems Practice Question
A user's Windows 10 computer fails to boot and displays the error "Bootmgr is missing". The technician boots from installation media and accesses the Windows Recovery Environment. Which command should be run to repair the Master Boot Record (MBR)?
⚠ Common exam trap
Many candidates confuse `bootrec /fixmbr` with `bootrec /fixboot` or assume `sfc /scannow` can fix boot-level corruption, when in fact only `bootrec /fixmbr` directly addresses the MBR.
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 a corrupted or missing Master Boot Record (MBR) or boot sector. The `bootrec /fixmbr` command writes a new MBR to the system partition, repairing the boot code without affecting the partition table. This is the correct tool in the Windows Recovery Environment for this specific symptom.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
chkdsk /r
Why it's wrong here
This command checks the file system for errors and locates bad sectors, recovering readable information. It does not write a new master boot record or repair the boot configuration data, so it cannot address a missing or corrupted MBR that prevents Windows from starting. In this scenario, the boot failure is at the partition table level, not the file system level, making chkdsk ineffective.
- ✗
sfc /scannow
Why it's wrong here
sfc /scannow verifies the integrity of protected system files and replaces corrupted versions with cached copies. However, the Master Boot Record is not a file within the Windows file system; it resides in the first sector of the disk. Therefore, sfc cannot repair the MBR, and any boot failure caused by MBR corruption will persist after a clean scan.
- ✓
bootrec /fixmbr
Why this is correct
This command writes a new Master Boot Record to the system partition without disturbing the existing partition table. It is the appropriate repair tool for a damaged or non-standard MBR, which is exactly the condition indicated by the boot failure. Running bootrec /fixmbr from the Windows Recovery Environment reconstructs the boot code that the BIOS loads to start Windows.
- ✗
dism /online /cleanup-image /restorehealth
Why it's wrong here
DISM repairs the Windows system image by checking for component store corruption and restoring health from Windows Update or a provided source. It operates on the operating system image's internal components, not on the disk's partition structure or boot sector. Thus, it can fix issues like system file corruption but cannot restore a missing or overwritten MBR.
Go deeper
Related to this question
Learn chapter
PXE Boot and Windows Deployment Services
Key term
Recovery
Recovery is the process of restoring systems, data, and operations after a security incident, failure, or disaster to return to normal functioning.
Key term
GUID Partition Table
A GUID Partition Table (GPT) is a modern standard for organizing and managing partitions on a storage drive, replacing the older Master Boot Record (MBR) system.
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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.