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XK0-006 Practice Question: A systems administrator is troubleshooting a…
A systems administrator is troubleshooting a server that fails to boot and displays the error: 'Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)'. Which TWO of the following are most likely causes? (Choose two.)
⚠ Common exam trap
It's easy for candidates to confuse a boot loader misconfiguration (Option E) with a root filesystem issue, but the kernel must successfully load before a VFS error can occur, so the problem lies after boot loader execution.
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
✓
Missing or misconfigured root filesystem in /etc/fstab
The error 'VFS: Unable to mount root fs on unknown-block(0,0)' indicates the kernel cannot locate or mount the root filesystem. A missing or misconfigured root filesystem entry in /etc/fstab (e.g., wrong device name, wrong UUID, or missing entry) prevents the kernel from mounting the root partition, leading to a kernel panic. The 'unknown-block(0,0)' specifically means the kernel cannot resolve the block device for the root filesystem.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Missing or misconfigured root filesystem in /etc/fstab
Why this is correct
Correct: If the root filesystem is missing or misconfigured, the kernel cannot mount it.
- ✗
Faulty RAM
Why it's wrong here
Incorrect: Faulty RAM usually causes random crashes or other panic messages, not this specific VFS error.
- ✓
Corrupted initramfs image
Why this is correct
Correct: The initramfs contains initial drivers and root filesystem; corruption leads to this error.
- ✗
Overwritten MBR
Why it's wrong here
Incorrect: A corrupted MBR prevents the boot loader from loading, so this error would not appear.
- ✗
Incorrect boot loader configuration pointing to wrong kernel
Why it's wrong here
Incorrect: If the boot loader points to a wrong kernel, the kernel would not load at all, resulting in a different error.
Visual reference
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Related to this question
Learn chapter
Navigating the Filesystem
Key term
Kernel
The kernel is the core program of an operating system that manages hardware resources and provides essential services for all other software to run.
Key term
fstab
fstab is a system configuration file in Linux that defines how and where storage devices and partitions are mounted at boot time.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This XK0-006 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 XK0-006 exam.