Is Windows Defender Enough? Defender vs Third Party Antivirus in 2025

I uninstalled my third‑party antivirus and — to my surprise — my PC felt faster, quieter, and no less protected; that small, impulsive change forced me to reassess a widely held belief: that piling an extra security vendor on top of Windows is always safer than trusting the built‑in stack. The MakeUseOf essay that sparked the conversation described exactly that experience: an antivirus that repeatedly froze the system, uninstalling it, and discovering that Windows’ own protections (cloud‑based machine learning, SmartScreen, kernel‑level integration, and reputation checks) were doing most of the heavy lifting. The author’s conclusion was blunt: for many users, the combination of modern Windows Security plus safer browsing habits can be a practical, lower‑friction way to stay secure. That claim is neither universally true nor merely opinion — it reflects real technical changes in Windows and important tradeoffs that every user should understand.

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Background / Overview: why Defender is no longer “basic”​

For the past decade Microsoft’s built‑in endpoint protection evolved from a lightweight signature scanner into a multi‑layered, cloud‑aware protection platform. Microsoft Defender (the consumer face of Windows Security) now integrates:

• Cloud‑delivered protection and automatic sample submission that let Defender query Microsoft’s cloud models and detonate suspicious files for near‑real‑time verdicts. This block‑at‑first‑sight capability is a core reason Defender can catch never‑before‑seen threats quickly.
• Behavioral and heuristic protections, including Attack Surface Reduction (ASR) rules and exploit mitigation features. These are designed to block living‑off‑the‑land techniques, script abuse, and common post‑exploitation activity.
• SmartScreen and reputation checks for downloads and web content, which can block or warn about software that lacks an established reputation. SmartScreen’s reputation signals are cloud‑based and integrate with the OS’s app‑execution controls.
• Smart App Control, a newer app‑execution control that blocks untrusted or malicious code before it runs (available on clean Windows 11 installs and evaluated via a learning period). This gives Windows a quasi‑application‑whitelisting capability without heavy admin work.
• Tamper protection, Controlled Folder Access (ransomware protections), memory integrity (HVCI), and tight integration with Windows Update and BitLocker, which together raise the baseline difficulty for attackers.

Independent lab testing has tracked this technical progress. AV‑TEST — a long‑standing industry benchmark — awarded Microsoft Defender top marks (6/6) in recent rounds, signaling that its detection, performance, and usability are competitive with many paid options. That’s a material change from the Windows 7 era, when Defender’s protection scores lagged much of the market. All of the above elevated Defender from a “basic scanner” to a defensible default for many users. But the picture is nuanced: integration matters, and “good enough” for everyday browsing is not the same as “sufficient” for every threat model.

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What the MakeUseOf piece actually argued (concise, verifiable summary)​

• The author had repeated system freezes and browser stutters while a third‑party antivirus ran. Uninstalling that antivirus removed the freezes and improved responsiveness. This is an empirical, single‑user observation; it’s plausible and consistent with performance complaints commonly seen in user forums about heavyweight or poorly configured security suites.
• They discovered that modern Windows Security already offers cloud ML, SmartScreen reputation checks, kernel‑level integration, and other defenses — and that Defender’s detection rates have improved dramatically compared with a decade ago. AV‑TEST results and Microsoft’s product documentation back up that assertion: Defender now leverages cloud‑scale telemetry and machine learning to block many new threats.
• The article warned that third‑party antivirus can actually increase risk: large, privileged codebases (antivirus engines and drivers) become high‑value targets; several vendors have had high‑severity flaws discovered in their components. Historically, Google Project Zero and other researchers have reported critical vulnerabilities in prominent antivirus code, demonstrating that extra software can widen the attack surface.
• The author concluded that, with careful habits (avoid risky downloads, use browser protections and extensions, keep Windows updated, and rely on Defender), many users can be safe without a paid third‑party antivirus, thereby avoiding the performance hits and pop‑ups that some suites generate. The piece framed the choice as a tradeoff: less friction and a smaller attack surface versus the additional protections and bundled features that premium suites provide.

This is a fair, measured summary of the essay’s claims — but it’s an anecdote, not a universal recommendation. The rest of this feature unpacks the tradeoffs, confirms the factual claims, and provides a practical, risk‑aware guide.

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The technical reality: third‑party AV increases both protection vectors and risk surface​

Putting more security software on a machine is a classic “defense‑in‑depth” idea: multiple independent vendors can provide independent checks. But every extra agent that runs with elevated privileges also adds code that can fail, be misconfigured, or be exploited.

• Antivirus products require deep system integration: kernel drivers, file‑system filters, network filters, and privileged services are common. Those components necessarily run with high privilege and interact with many file formats, parsers, and protocols — making them attractive targets for exploit chaining. Google Project Zero and independent researchers have repeatedly demonstrated critical vulnerabilities in antivirus components (Symantec/Norton and others), sometimes resulting in remote code execution or kernel corruption. Those findings show the conceptual risk: the more privileged code you run, the more tempting it is for attackers to target it.
• Recent, concrete examples underline the point. In 2025 the Zero Day Initiative publicly disclosed CVE‑2025‑3500 — a high‑severity integer overflow in Avast’s aswbidsdriver kernel component that could allow local privilege escalation and arbitrary kernel code execution. Avast issued a patch the same month; the advisory and vendor response illustrate the real danger when a widely deployed security driver contains exploitable logic. This is not theoretical: it’s an empirical demonstration of how a protective product can become the attack vector.

Those findings don’t imply that all third‑party AVs are unsafe. Rather, they emphasize a tradeoff: third‑party suites can add detection capabilities (sometimes excellent), but they also increase the size and privilege of the codebase on the host.

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Performance, UX, and “security fatigue”: real costs that matter​

A recurring, under‑reported harm from consumer security suites is the subtle erosion of user attention and system performance.

• Many users complain about long scans, slower boot times, and background spikes during updates and signature refreshes. Those issues are configuration‑sensitive, but poorly tuned or older suites can introduce perceptible system lag — which is exactly what the MakeUseOf author experienced. Community discussions reflect these frustrations, with users reporting pop‑ups, upgrade nags, and occasional freezes that disappear after uninstalling the vendor product.
• Constant promotional or alarmist UI (e.g., “Your PC may be at risk!” banners) leads to security fatigue: users learn to dismiss warnings, including legitimate ones. That conditioning is hazardous: if every UI prompt looks like marketing, real alerts are ignored. Removing an intrusive vendor can therefore increase effective vigilance, albeit at the cost of reduced layered detection.
• The performance benefit of removing a resident AV varies widely: modern engines are far more efficient than a decade ago, and independent lab tests typically measure performance impact before assigning awards. But the subjective experience (smoothness, responsiveness) matters to users, and there is no universal measurement that captures every context. AV‑Comparatives and other labs provide real‑world protection and performance metrics that can help guide a decision.

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The limitations of both models: Defender‑only vs. layered third‑party​

Neither “Defender only” nor “third‑party stack” is a universal panacea. Each model has realistic benefits and known limitations.
Strengths of Defender (built‑in):

• Deep OS integration: updates and features ship with Windows updates and the platform's telemetry, enabling coordinated mitigations and tamper protection.
• Minimal friction for most users: no additional UI clutter, fewer vendor pop‑ups, and reduced management overhead.
• Competitive detection in modern lab tests — Defender receives top scores in recent AV‑TEST runs and performs well in AV‑Comparatives real‑world tests.

Weaknesses of Defender:

• Some advanced enterprise features (full EDR, deep forensic investigation, extended telemetry) require Microsoft Defender for Endpoint licenses. For high‑value environments, Defender’s free consumer package may be insufficient without EDR and centralized management.
• Smart App Control and some protections require a clean install or specific configuration; they are not automatic for every upgrade path. That limits immediate availability of certain app‑control protections.

Strengths of third‑party suites:

• Many vendors bundle features users value: managed VPNs, identity/breach monitoring, cross‑platform device protection, non‑Edge browser integrations, and premium support. Those extras can be decisive for some households or businesses.
• Some third‑party engines still outperform in niche detection categories or add specialty heuristics.

Weaknesses of third‑party suites:

• Extra privileged code and drivers increase the attack surface (see Project Zero and ZDI findings).
• Potential for conflicts with Defender, heavier system footprint, and intrusive upsell UI that conditions users to habitually dismiss warnings.

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Who can reasonably run with Defender only — and who shouldn’t​

A one‑size‑fits‑all answer is dangerous. Consider your threat model:

• Defender‑only is a reasonable baseline if:
• You are a home user with a modern, fully patched Windows 10/11 system and you practice good browser hygiene (don’t download unknown executables, avoid risky attachments, use a password manager and MFA).
• You primarily use Microsoft Edge (SmartScreen is integrated best there) and you enable Windows security features (cloud protection, Controlled Folder Access, Tamper Protection, Smart App Control where available).
• You are comfortable adding non‑resident, on‑demand scanners (e.g., Malwarebytes or ESET online scanners) for occasional second opinions rather than running two real‑time engines.
• Consider third‑party or additional protections if:
• You handle sensitive corporate data, manage other people’s endpoints, or work in finance/healthcare where compliance and EDR are required.
• You run unsupported OS versions, or you use non‑Windows platforms that require vendor cross‑platform support.
• You need vendor features not available in Defender (e.g., specific VPN, parental controls across platforms, or identity‑theft monitoring).

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Practical, risk‑aware steps if you try Defender‑only​

If the decision is to trust Windows Security as your primary defense, do the configuration and habit changes that matter most. This is a short, clear checklist — follow this before removing a second AV:

• Create a full backup (system image) and a recovery plan — never remove a protection layer without a rollback.
• Ensure Windows Update is enabled and fully patched. Security fixes are the first line of defense.
• In Windows Security:
• Turn on Cloud‑delivered protection and Automatic sample submission. These enable block‑at‑first‑sight behavior.
• Enable Tamper protection, Controlled Folder Access, Real‑time protection, and ASR rules appropriate for your workflows.
• Check App & browser control and enable SmartScreen checks for downloads and apps.
• Harden the browser: enable phishing protection, disable risky plugins, and add reputable content‑security extensions (uBlock Origin, HTTPS‑Everywhere style policies, script blockers for advanced users).
• Use a non‑privileged daily account (standard user) for routine tasks; only use admin accounts when necessary.
• Enable full‑disk encryption (BitLocker) and enable Secure Boot/Memory Integrity where the hardware supports it.
• Consider an on‑demand scanner (run monthly) and use browser reputation lists and a password manager with MFA.
• If you’re part of a managed network, consult IT before removing company‑mandated endpoint protection.

Following these steps leaves you with a modern, layered OS‑level defense and a sensible behavioral baseline. It’s not “no protection”; it’s a different balance of friction, transparency, and risk.

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If you keep or choose a third‑party suite: how to reduce harm​

If you decide a paid or third‑party AV still fits your needs, reduce secondary risks:

• Avoid running two resident real‑time engines simultaneously. They often conflict and can reduce stability. Use Defender as a passive fallback or disable overlapping resident features per vendor guidance.
• Keep the vendor software fully patched and enable automatic updates; many high‑severity vendor flaws are fixed quickly once disclosed (ZDI example with Avast shows the vendor patching promptly).
• If your vendor installs kernel drivers or network filters, check their update cadence and transparency — vendors with rapid security response and public advisories are preferable.
• Monitor vendor UI behavior: avoid aggressive upgrade nags and consider paying for minimalist, no‑nonsense editions if vendor bundling is a problem.

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Critical analysis: strengths of the MakeUseOf argument and where it risks being misleading​

What the MakeUseOf piece got right:

• It captured a real, relatable phenomenon: third‑party AV can feel intrusive and can degrade system responsiveness while sometimes delivering only marginal gains for low‑risk users.
• It highlighted a major evolution: Defender is a far stronger, cloud‑backed product today than it was a decade ago. Lab results corroborate that improvement.
• It correctly identified a complex truth: more privileged code can enlarge the attack surface — security software has been a target for vulnerability research.

Where the article under‑states the risk or could mislead:

• The essay is an anecdote. While useful and instructive, one person’s trouble‑free months without a third‑party AV do not equal statistical safety. Survivorship bias is real: many users who remove aggressive suites will run into trouble eventually — but those cases are less likely to be written about in a single anecdote. Community forums show both outcomes (smooth operation vs. eventual compromise).
• Defender’s “good enough” status depends on configuration (cloud protection on, updates enabled) and user behavior (patched OS, cautious browsing). Without these, the risk increases quickly.
• The article mentions vendor vulnerabilities as a reason to remove AV, which is reasonable to consider — but the alternative (no third‑party AV) is not risk‑free; attackers exploit many vectors (phishing, credential stuffing, supply‑chain) that require both user behavior and layered controls to mitigate. The choice should be contextual and risk‑based, not purely reactive.

Where claims were unverifiable:

• Any claim of “my PC is now safer” is subjective and hard to verify scientifically without controlled telemetry or incident data. That claim should be treated as a personal outcome, not proof that the strategy is safer for every reader.

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Final recommendations: a practical, balanced checklist​

• If you are a typical home user with an up‑to‑date Windows 10/11 PC, enable all Defender features listed earlier, practice safe browsing, and use a password manager with MFA. That is a defensible, low‑friction posture.
• If you handle sensitive data, are responsible for others’ endpoints, or need cross‑platform bundled services, keep a reputable paid vendor and ensure it is configured to avoid overlapping real‑time agents.
• Never treat any single control as sufficient: combine OS‑level protections, secure configurations, strong passwords, MFA, cautious email behavior, backup and recovery plans, and occasional on‑demand scanning.
• Keep software patched and monitor vendor advisories. When vendors release urgent fixes (as in the Avast ZDI advisory), apply them promptly.

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Modern Windows Security has legitimately closed the gap it once had with third‑party vendors — and for many users that makes Defender a practical, low‑friction foundation. But removing a security agent to avoid pop‑ups or speed issues is a tactical move that must be followed by deliberate hardening and safer habits. The MakeUseOf author’s experience is instructive: it shows that how you configure your system and how you behave matters more than the brand of your resident antivirus. The right answer is a risk‑based one: for some users Defender alone — correctly configured and combined with sane habits — is sufficient; for others, an additional vendor or enterprise EDR remains necessary. Choose the model that matches your threat profile, harden the stack you run, and always keep recovery and patching plans ready.

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Source: MakeUseOf I deleted my antivirus, and somehow my PC is now safer