The answer is that the SATA mode was changed from AHCI to IDE, which causes a boot failure because the operating system’s storage driver expects the AHCI controller, not the legacy IDE emulation. When the SATA mode is switched to IDE, the OS cannot load the correct driver for the hard drive, resulting in a “boot device not found” error—even though the drive itself is physically fine. On the CompTIA A+ Core 1 220-1201 exam, this scenario often appears after a CMOS reset or an accidental BIOS change, testing your understanding of how SATA controller modes interact with the OS driver stack. A common trap is assuming the drive is dead; instead, remember that AHCI enables advanced features like NCQ and hot-swapping, while IDE is a legacy compatibility mode. Memory tip: “AHCI is Active, IDE is Idle”—if the BIOS reverts to IDE, the driver goes idle and the boot fails.
220-1201 BIOS / UEFI Practice Question
This 220-1201 practice question tests your understanding of bios / uefi. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A user reports that their computer suddenly cannot find the boot device, and the BIOS shows the SATA mode is set to 'IDE' instead of 'AHCI'. The drive was previously working. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The SATA mode was changed to IDE
If the SATA mode is changed from AHCI to IDE, the OS driver may not load, causing a boot failure. This can happen after a CMOS reset or accidental BIOS change. The question tests understanding of SATA controller modes and their impact on booting.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The hard drive has failed
Why it's wrong here
A failed drive would typically not be detected at all, or would make unusual noises.
✗
The SATA cable is loose
Why it's wrong here
A loose cable would cause intermittent detection, not a consistent mode change.
✗
The CMOS battery is failing
Why it's wrong here
A failing battery resets all settings, including SATA mode, but the mode change itself is the direct cause, not the battery.
✓
The SATA mode was changed to IDE
Why this is correct
Windows installed in AHCI mode will not boot in IDE mode without driver changes, leading to a boot device not found error.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 220-1201 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 220-1201 question in full detail.
Identify which 220-1201 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
BIOS / UEFI — This question tests BIOS / UEFI — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The SATA mode was changed to IDE — If the SATA mode is changed from AHCI to IDE, the OS driver may not load, causing a boot failure. This can happen after a CMOS reset or accidental BIOS change. The question tests understanding of SATA controller modes and their impact on booting.
What should I do if I get this 220-1201 question wrong?
Identify which 220-1201 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A user reports that their new SSD is not recognized by the system. The drive is properly connected and powered. Which UEFI setting should be checked to ensure the drive is detected?
easy
A.Enable Secure Boot
✓ B.Set SATA mode to AHCI or RAID as appropriate
C.Disable the TPM chip
D.Change boot order to list the SSD first
Why B: The correct answer is to check the SATA configuration mode. If the SATA controller is set to RAID or AHCI when the drive requires the other, or if it's disabled, the drive may not be detected. This tests understanding of how UEFI/BIOS settings affect hardware enumeration.
Last reviewed: Jun 18, 2026
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This 220-1201 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 220-1201 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.