MD-102 Manage applications Practice Question
Your organization deploys Microsoft Defender for Endpoint (now Microsoft Defender XDR) on Windows 10 devices using Intune. After deployment, some devices show 'Defender service is not running' in the security console. The devices are online and compliant. What is the most likely cause?
⚠ Common exam trap
Test-takers frequently assume tamper protection (Option A) is the culprit because it is a common security feature, but they overlook the automatic disabling behavior triggered by a third-party antivirus registration in the Windows Security Center.
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
✓
A third-party antivirus is installed and active.
When a third-party antivirus is installed and active on a Windows 10 device, Windows Defender (now Microsoft Defender Antivirus) automatically disables itself to avoid conflicts. This is by design: the Windows Security Center detects the active third-party AV and sets Defender's service state to stopped or disabled. In the Microsoft Defender for Endpoint console, this appears as 'Defender service is not running' even though the device is online and compliant with Intune policies.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Tamper protection is enabled and blocking the service.
Why it's wrong here
Tamper protection prevents disabling real-time protection or changing settings, but it does not stop the Defender service from starting; a blocked service would itself be the symptom, not the cause. Tamper protection is the right control when admins must be prevented from turning off protection.
- ✗
The devices are not compliant with the Defender policy.
Why it's wrong here
Compliance state reflects policy evaluation, not service health; the stem already states the devices are compliant, so this cannot explain a stopped Defender service. Compliance policies are used to gate conditional access, not to report whether a security service is running.
- ✗
Windows Firewall is blocking Defender updates.
Why it's wrong here
Windows Firewall filters network traffic; it does not govern local service startup, and Defender updates failing would leave signatures stale rather than stop the service. Firewall rules are the correct fix when cloud-delivered protection or update endpoints are unreachable.
- ✓
A third-party antivirus is installed and active.
Why this is correct
When a third-party antivirus is installed and active, it registers with the Windows Security Center and disables Microsoft Defender Antivirus, so the Defender service stops running. Intune's onboarding then reports the service as not running despite the device being online and compliant.
Go deeper
Related to this question
Learn chapter
Managing Microsoft 365 Apps and Office Updates
Key term
Microsoft Defender XDR
Microsoft Defender XDR is a unified security platform that automatically correlates alerts from across an organization's endpoints, email, identities, and cloud apps to stop complex attacks.
Key term
Intune
Microsoft Intune is a cloud-based service that helps organizations manage their users' devices and applications, ensuring security and compliance without needing to own or control the physical hardware.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This MD-102 practice question is part of Courseiva's free Microsoft 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 MD-102 exam.