Resolving Windows Defender High CPU Usage


  • Scan your system for malware conflicts using Windows Defender and remove any detected threats.
  • Temporarily disable other security software to check for conflicts.
  • Ensure that your operating system and Windows Defender are up to date.
  • Exclude specific folders from scans to reduce CPU usage.

Experiencing high CPU usage with Windows Defender? Here’s how I resolved it.

Scanning for Malware Conflicts

When experiencing high CPU usage with Windows Defender, it is important to scan for malware conflicts to identify the root cause. Follow these steps to scan your system and resolve the issue:

1. Open the Windows Defender application by clicking on the Windows Start menu and typing “Windows Defender” in the search bar. Select the Windows Defender Security Center from the search results.

2. In the Windows Defender Security Center, click on the “Virus & threat protection” tab.

3. Under the “Current threats” section, click on the “Quick scan” or “Full scan” option to initiate a scan of your system. Choose the appropriate scan option based on your needs.

4. Allow the scan to complete. Windows Defender will automatically detect and remove any malware or potentially unwanted programs.

5. If the high CPU usage issue persists, consider temporarily disabling other security software such as antivirus programs or firewalls to check for conflicts. Consult the documentation or support resources for the specific software you are using.

6. Ensure that your operating system and Windows Defender are up to date. Check for updates by going to the Windows Update section in the Control Panel or Settings.

Excluding Specific Folders from Scans

  • Open Windows Security by clicking on the Start menu and selecting Settings.
  • In the Settings window, click on Update & Security.
  • From the left-hand menu, select Windows Security.
  • Click on Virus & threat protection to access the antivirus settings.
  • Under the Current threats section, click on the Scan options link.
  • Scroll down and click on Exclusions under the Windows Defender Antivirus options section.
  • Click on the Add an exclusion button.
  • Choose the type of exclusion you want to add (e.g., Folder).
  • Click on the Select folder button to choose the folder you want to exclude from scans.
  • Browse and select the specific folder you wish to exclude.
  • Click on the Open button to confirm the folder selection.
  • Review the added exclusion in the Exclusions list.
  • Repeat steps 7-12 if you need to exclude additional folders.
  • Once all desired exclusions are added, close the Exclusions window.
  • Close the Scan options window.
  • Close the Windows Security window.

Managing Defender’s Resource Allocation

Resource Allocation
CPU By default, Windows Defender is set to use a significant portion of CPU resources. To manage resource allocation, you can adjust the scanning schedule and exclusions list to minimize high CPU usage.
Memory Windows Defender consumes a certain amount of memory while running scans or real-time protection. To optimize resource allocation, you can schedule scans during idle periods and avoid running memory-intensive applications simultaneously.
Storage Windows Defender regularly updates its virus definitions and stores them locally. This can consume storage space over time. To manage allocation, you can periodically clean up old definitions and adjust the frequency of updates.
Network Windows Defender relies on network connectivity for downloading updates and cloud-based protection. To avoid excessive use of network resources, you can configure update settings to download updates during non-peak hours or limit the bandwidth used by Windows Defender.


Why is Windows Defender taking up 100% CPU?

Windows Defender takes up 100% CPU because it may be running background scans, including full scans, while other programs are in use. To resolve this, you can reschedule Windows scans to occur when you are not actively using your computer by accessing Task Scheduler through the Start Menu.

How do I fix 100% CPU usage on Windows?

To fix 100% CPU usage on Windows, you can follow these steps:

1. Identify the process causing high CPU usage.
2. Close unnecessary applications or put them to sleep.
3. Scan your PC for malware.
4. Update outdated drivers and software.
5. Reset power settings.
6. Turn off Windows notifications.
7. Disable P2P sharing.
8. Disable Cortana in the Registry Editor.

How do I make Windows Defender use less CPU?

To make Windows Defender use less CPU, you can adjust the Max CPU Usage setting. This can be done by using the command “Set-MpPreference -ScanAvgCPULoadFactor” followed by a chosen percentage between 5 and 100.