3 Ways to Resolve Microsoft Defender’s High CPU Usage Issue

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Title: 3 Ways to Resolve Microsoft Defender’s High CPU Usage Issue

Meta Description: Is Microsoft Defender slowing down your PC? Here are three effective ways to fix high CPU usage and get your computer running smoothly again.

Introduction

Microsoft Defender is built into Windows to keep your system safe from malware and other threats. But sometimes, it can go overboard — using too much CPU power and slowing everything down. If you’ve noticed your fan running loud or your PC lagging when Defender is active, don’t worry. Here are three proven fixes to bring CPU usage back to normal.

1. Limit Microsoft Defender’s CPU Usage via PowerShell

By default, Microsoft Defender can use up to 100% of your CPU during scans. You can cap that usage to a safer level, like 30% or 50%, with a simple PowerShell command.

Steps:

1. Press Windows + X and select Windows PowerShell (Admin).
2. Type this command and press Enter:
   Set-MpPreference -ScanAvgCPULoadFactor 30
   (You can change “30” to any value between 5 and 100.)
3. Restart your computer.

This will limit how much CPU power Defender uses during background scans.

2. Exclude Large or Trusted Folders from Scans

Defender sometimes gets stuck scanning massive folders (like those containing large projects or game files). If you know certain folders are safe, you can exclude them from real-time scanning.

Steps:

1. Open Windows Security → Virus & threat protection → Manage settings.
2. Scroll down to Exclusions → Add or remove exclusions.
3. Click Add an exclusion → choose Folder, and select the one you want to skip.

This will stop Defender from repeatedly scanning trusted files and lighten CPU load significantly.

3. Turn Off Real-Time Protection Temporarily (If Safe)

If you’re running another trusted antivirus or performing heavy tasks like video rendering, temporarily disabling real-time protection can free up CPU resources.

Steps:

1. Go to Windows Security → Virus & threat protection → Manage settings.
2. Toggle off Real-time protection.

⚠️ Important: Turn it back on once you’re done. Keeping it off permanently leaves your system vulnerable.

Final Thoughts

High CPU usage from Microsoft Defender usually means it’s working hard to keep your system secure — but it shouldn’t drag your PC down. Limiting scan intensity, excluding large folders, or briefly disabling real-time protection can all help.

If none of these fixes work, consider running a Windows Update or checking for malware that might be tricking Defender into overworking.

Mark Vincent

Tech enthusiast and content creator passionate about making technology simple for everyone. I share practical tips, guides, and reviews on the latest in computers, software, and gadgets. Let’s explore the digital world together!