The answer is a depleted or failing CMOS battery. This is correct because the CMOS checksum error occurs when the system’s BIOS/UEFI settings—such as date, time, and hardware configuration—cannot be properly saved and verified at startup; the checksum is a calculated value stored in CMOS memory, and if the battery powering that memory is dead, the stored data becomes corrupted or lost, triggering the error and forcing the firmware to re-detect hardware, which causes the long boot delay. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of common motherboard-level symptoms and the role of the coin-cell battery (typically CR2032) in retaining volatile CMOS data. A common trap is to suspect a failing hard drive or corrupted OS, but the key clue is the time/date resetting to a default year. Memory tip: think “Checksum = Battery Sum”—if the sum doesn’t add up, the battery is likely drained.
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 customer complains that their computer takes a very long time to boot and sometimes shows a 'CMOS Checksum Error' before starting. What is the most likely hardware issue?
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 CMOS battery is depleted
A CMOS checksum error indicates that the BIOS/UEFI settings are not being retained, often due to a failing or dead CMOS battery. This causes time/date resets and boot delays as the firmware re-detects hardware. This tests knowledge of common CMOS-related symptoms.
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 is failing
Why it's wrong here
A failing drive would cause different errors like bad sectors or boot failure, not a CMOS checksum error.
✗
The RAM module is faulty
Why it's wrong here
Faulty RAM typically causes random crashes or beep codes, not checksum errors.
✓
The CMOS battery is depleted
Why this is correct
The battery powers the CMOS memory that stores settings; when low, settings are lost.
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.
✗
The UEFI firmware is corrupted
Why it's wrong here
Corrupted firmware would cause a different error and likely prevent boot entirely.
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 CMOS battery is depleted — A CMOS checksum error indicates that the BIOS/UEFI settings are not being retained, often due to a failing or dead CMOS battery. This causes time/date resets and boot delays as the firmware re-detects hardware. This tests knowledge of common CMOS-related symptoms.
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 technician is troubleshooting a server that randomly resets the time and date to 2000 after being powered off for a few hours. The system otherwise boots and runs normally. Which component is most likely failing?
medium
A.The power supply unit is failing
B.The motherboard clock crystal is defective
✓ C.The CMOS battery needs replacement
D.The UEFI firmware has a bug
Why C: The CMOS battery maintains the real-time clock and UEFI settings when power is off. If it fails, the time resets and settings may be lost. This tests the ability to distinguish between battery failure and other hardware issues.
Last reviewed: Jun 18, 2026
Question Discussion
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