EDR vs. antivirus: How they differ and why most businesses need both

Antivirus has been the default endpoint security tool for decades — and for good reason. It works reliably against the threats it was designed to stop. But the threat landscape has changed significantly, and many of the attack techniques that cause the most damage today, including fileless malware, zero-day exploits and ransomware with behavioral evasion, fall outside what traditional antivirus was built to detect.

Endpoint detection and response (EDR) address that gap. But that doesn’t mean antivirus is obsolete. Understanding what each tool does, where each one falls short and how they complement each other is more useful than treating the comparison as a simple upgrade question.

Kaseya offers both Datto EDR and Datto AV, which puts us in a practical position to explain exactly where each one fits and why most MSPs and businesses are better served by running them together.

What is the difference between EDR and antivirus?

Both tools protect endpoints from malware. The difference lies in how they detect threats, what they do when they find one and how much visibility they give the security team afterward.

Antivirus

Antivirus software scans files and processes for known malware signatures. When a file matches a known threat in the vendor’s database, the antivirus blocks or quarantines it. Traditional antivirus is fast, lightweight and highly effective against the massive volume of known malware that circulates constantly across the internet.

Modern antivirus has evolved significantly beyond signature matching. Next-generation antivirus (NGAV) incorporates machine learning, AI and heuristic analysis to detect suspicious behavior even when a specific file signature isn’t in the database. Datto AV, for example, uses AI and machine learning to identify and block zero-day threats, polymorphic malware and potentially unwanted applications, going well beyond the capabilities of legacy signature-based tools.

That said, even next-generation antivirus is primarily a prevention tool. Its goal is to block threats before they execute. What it doesn’t typically provide is the telemetry, investigation capability and response tooling needed to understand what happened after a threat has already run.

Détection et réponse des points de terminaison (EDR)

EDR takes a different approach. Rather than focusing primarily on blocking known threats, EDR continuously monitors endpoint behavior: process execution, file changes, registry modifications, network connections and authentication events. When activity deviates from a normal behavioral baseline, the platform flags it for investigation.

EDR is designed for threats that get through the prevention layer, whether because they’re unknown at detection time, fileless, or specifically crafted to evade signature-based tools. When an incident is confirmed, EDR provides automated response actions including endpoint isolation, process termination and file quarantine, alongside detailed forensic data that security teams can use to trace the attack’s full path.

For the full rundown of EDR, see our guide to endpoint detection and response.

EDR vs. antivirus: Key differences

The core distinction is prevention versus detection and response. Antivirus is built to stop known threats at the gate. EDR is built to catch what gets through and respond before it spreads.

Prevention versus detection

Antivirus works at the entry point. Its job is to stop threats from executing in the first place, which it does extremely well for the enormous volume of commodity malware that attacks endpoints every day. Kaspersky’s detection systems flagged an average of 500,000 malicious files per day in 2025 alone, and most of that volume is handled by antivirus without ever escalating to human review.

EDR operates after the entry point. It assumes that some threats will get through and monitors for what happens next. That assumption is well-founded: fileless attacks and living-off-the-land techniques now account for the majority of critical incidents, leveraging memory execution and legitimate system tools rather than traditional files and therefore producing nothing for signature-based detection to catch.

Visibility and forensics

After an incident, antivirus can tell you that a file was quarantined. EDR can tell you which process spawned the threat, which user account was active, what network connections were made, what files were modified and exactly how the attack progressed from initial execution to lateral movement. That forensic depth is what makes root cause analysis and cyber insurance claims possible.

Response capability

Antivirus blocks and quarantines. EDR isolates, terminates, rolls back and documents. In an active ransomware scenario, the ability to isolate an endpoint from the network in seconds, before the encryption routine completes and before lateral movement begins, can be the difference between a contained incident and an organization-wide outage.

When to use EDR

EDR’s value is most apparent against the threats that get through the antivirus layer and against attacks that were never detectable by signatures in the first place. These are the scenarios where EDR is the right tool to have in place:

Behavioral detection for unknown threats
EDR doesn’t need a signature to detect a threat. It monitors how processes behave and flags activity that deviates from a normal baseline, regardless of whether the malicious file or technique has been seen before. This is the capability that makes EDR effective against zero-day exploits, novel ransomware variants and custom-built attack tools.

Fileless attack detection
Fileless attacks execute entirely in memory and leave no file on disk for antivirus to scan. According to ReliaQuest’s 2024 Annual Threat Report, 86.2% of detections associated with critical incidents involved fileless malware. EDR’s process-level behavioral monitoring is one of the few reliable ways to detect these attacks before significant damage is done.

Rapid containment
When EDR detects a confirmed threat, it can isolate the affected endpoint from the network immediately, cutting off lateral movement before it reaches adjacent systems. This containment speed directly determines the blast radius of an incident.

Forensic depth for investigation and compliance
The process trees, file modification logs, network connection records and attack timelines that EDR produces are essential for post-incident investigation. They’re also increasingly required by cyber insurers and compliance frameworks as evidence that continuous monitoring was in place and that the incident was properly investigated.

MITRE ATT&CK alignment
EDR alerts that map to the MITRE ATT&CK framework give analysts immediate context on the attacker’s likely technique and the next step in the attack chain. That context reduces investigation time significantly compared to raw alert data without structured framework alignment.

When to use antivirus

Antivirus remains a foundational layer in any endpoint security stack, and there are clear circumstances where it’s the right tool to lead with or rely on most heavily. These include:

High-volume known threat prevention
The vast majority of malware encountered by business endpoints is known, catalogued and detectable by antivirus. For SMBs that face opportunistic attacks rather than targeted intrusions, a well-configured next-generation antivirus catches most threats automatically, without requiring analyst review or manual response. That automation at scale is genuinely valuable.

Low operational overhead
Antivirus is designed to run quietly in the background. Modern tools like Datto AV have a footprint under 1GB, run real-time scanning without measurable impact on system performance and require minimal configuration to deliver consistent protection. For lean IT teams, that simplicity matters.

Fast deployment across large estates
Antivirus agents are typically faster to deploy and easier to manage at scale than EDR. For MSPs rolling out endpoint protection across many clients simultaneously, antivirus is the faster, lower-friction starting point.

Cost-effectiveness
Antivirus is generally less expensive to license than EDR, making it accessible for organizations with limited security budgets. When budget constrains which tools can be deployed, antivirus delivers the best return against the highest volume of threats at the lowest price point.

First line of defense
Even in environments running full EDR, antivirus serves as the initial filter that intercepts high-volume commodity threats automatically, reducing the alert load that reaches analysts and letting the EDR focus on more sophisticated activity.

Can EDR replace antivirus?

This is the most common question in the EDR versus antivirus comparison, and the short answer is: technically possible, but not recommended.

EDR can detect many of the same threats that antivirus catches, including known malware, through its behavioral analysis and threat intelligence feeds. Some organizations have moved to EDR-only deployments and achieved acceptable coverage. But there are practical reasons why running both is the stronger choice for most organizations.

Antivirus is optimized for high-volume known threat prevention. It catches commodity malware automatically, at scale, without generating the kind of alert detail that requires analyst review. Running antivirus alongside EDR means the EDR’s investigation and response capabilities are reserved for the threats that actually warrant that attention, rather than being consumed by the background noise of commodity malware that antivirus would have stopped in seconds.

There’s also a depth-of-prevention argument. Antivirus stops a threat before it executes. EDR detects it after it begins executing. In a layered security model, stopping the threat earlier in the chain, before it has run any code on the endpoint, is always preferable to catching it mid-execution. The two tools operate at different stages of the attack lifecycle and are more effective in combination than either is in isolation.

How antivirus with EDR strengthens endpoint security

The most effective endpoint security posture combines antivirus for prevention and EDR for detection and response. This isn’t just a theoretical recommendation: it’s measurable.

According to independent testing by Miercom, a global cybersecurity testing organization, Datto AV combined with Datto EDR detects and stops 99.62% of all malware. The two products are designed to operate from a single unified interface, share the same agent infrastructure and feed telemetry into the same console, which means there’s no operational overhead from running them together and no context-switching between tools.

In practice, the combined deployment works as a two-stage defense:

1. Datto AV intercepts and blocks the high volume of known malware, commodity ransomware and potentially unwanted applications before they execute.
2. Datto EDR monitors behavioral activity on the endpoint and catches anything that gets through the antivirus layer: fileless attacks, zero-day exploits, novel ransomware variants and post-exploitation activity.

For MSPs, this combination simplifies the security conversation with clients. Rather than choosing between prevention and detection, clients get both, integrated, from a single platform.

Which do you need?

The right starting point depends on your current security posture, your team’s capacity and the risk profile of the environments you’re protecting.

Start with antivirus if:

• You’re building endpoint protection from scratch and need immediate coverage at the lowest cost and complexity
• Your primary concern is commodity malware and known threats rather than targeted attacks
• Your clients are in low-risk industries with limited compliance requirements
• You need a fast, lightweight solution that requires minimal ongoing management

Add EDR if:

• You’re dealing with clients in regulated industries where continuous monitoring and incident documentation are required
• You want visibility into what happens after a threat gets through the prevention layer
• Your environment is at elevated risk from ransomware, fileless attacks or targeted intrusions
• You need forensic capability for post-incident investigation or cyber insurance requirements

For most MSPs and businesses, the answer is both. Antivirus handles prevention. EDR handles detection and response. Together they cover the full attack lifecycle at the endpoint. Datto AV and Datto EDR are built to work as a combined solution, deployed and managed from a single interface within the Kaseya platform. The Miercom-verified 99.62% malware detection rate reflects exactly that combined model.

Prevent, detect and respond with Kaseya

The EDR vs. antivirus comparison isn’t really a question of which one to choose. It’s a question of understanding what each tool does and building a stack where both layers are working together.

Antivirus prevents. EDR detects and responds. For the businesses and MSPs navigating an endpoint threat landscape where 500,000 new malicious files emerge every day and fileless malware accounts for the majority of critical incidents, running both is the clearest path to comprehensive endpoint coverage.

Datto AV provides next-generation antivirus protection with AI-driven threat prevention, tamper resistance and a lightweight footprint that won’t impact system performance. Datto EDR provides continuous behavioral monitoring, MITRE ATT&CK-aligned detection and one-click response actions. Both integrate natively with Kaseya’s RMM offerings and are built for delivery at scale.