Resolve High CPU and Disk Usage Caused by Avast on Windows 10/11

Resolve High CPU and Disk Usage Caused by Avast on Windows 10/11

Avast is one of the most popular free antivirus programs for Windows users. While it offers good protection and helpful features, many users have reported that Avast’s background services consume high CPU or disk resources, especially on Windows 10 and Windows 11.

This problem can cause system slowdowns, lag, fan noise, and even unresponsiveness. If you’ve opened Task Manager and seen Avast Service (AvastSvc.exe) using a large portion of your CPU or disk, this guide will walk you through effective ways to reduce its impact.

Why Is Avast Using High CPU or Disk?

Here are some common causes behind the issue:

• Real-time protection scanning too aggressively

• Background processes such as Cleanup, Mail Shield, or Software Updater

• Outdated version of Avast or corrupted files

• Conflicts with Windows Defender or other third-party tools

• Scheduled scans running frequently

• Bugs or misconfigurations in Avast’s settings

Now, let’s look at practical ways to fix this issue.

Fix 1: Update Avast to the Latest Version

Sometimes high resource usage is caused by bugs in older versions of Avast. Updating the software can often fix performance issues.

How to update:

1. Open Avast Antivirus

2. Click Menu > Settings

3. Go to General > Update

4. Under Program, click Check for updates

5. Restart your PC after the update

Keeping Avast up to date ensures you get the latest bug fixes and performance improvements.

Fix 2: Disable Avast Cleanup (If Installed)

Avast Cleanup Premium is known to use a significant amount of system resources in the background. If you don’t actively use this feature, disabling or uninstalling it can help.

To disable Cleanup:

1. Open Avast

2. Go to Menu > Settings > Performance

3. Find Cleanup Premium

4. If it’s running, click to disable it

To uninstall Cleanup:

1. Open Control Panel > Programs > Programs and Features

2. Find Avast Cleanup Premium and uninstall it

Fix 3: Disable Unnecessary Avast Shields

Avast runs several shields in real time, such as File Shield, Mail Shield, and Behavior Shield. While they improve security, you might not need them all.

To manage shields:

1. Open Avast

2. Click Protection > Core Shields

3. Toggle off any shields you don’t use, such as Mail Shield or Behavior Shield

Disabling non-essential shields can reduce CPU usage without sacrificing core protection.

Fix 4: Adjust Avast Scan Frequency

If Avast is scanning too often, it can significantly impact performance.

Modify scan settings:

1. Open Avast

2. Go to Protection > Virus Scans

3. Choose the scan you want to adjust (e.g., Full Scan)

4. Click Settings (gear icon)

5. Under Frequency, reduce the scan frequency or set scans to run during idle times

You can also switch scheduled scans to run weekly instead of daily.

Fix 5: Add Avast to Windows Defender Exclusion List

Even though Avast disables parts of Windows Defender when active, some background scanning may still cause conflicts and double scanning.

To add an exclusion:

1. Go to Settings > Privacy & Security > Windows Security > Virus & Threat Protection

2. Click Manage settings

3. Scroll to Exclusions, click Add or remove exclusions

4. Add the Avast folder:

   makefile

   C:\Program Files\Avast Software


This can prevent unnecessary conflict between Avast and Windows Defender.

Fix 6: Repair Avast Installation

A corrupted installation may cause performance issues.

How to repair Avast:

1. Open Control Panel > Programs > Programs and Features

2. Select Avast Antivirus

3. Click Uninstall/Change, then select Repair

4. Follow on-screen instructions

5. Restart your PC

This option reinstalls critical files without deleting your settings.

Fix 7: Disable Avast Reputation Services and HTTPS Scanning

Some background services like Reputation Services and HTTPS Scanning are resource-intensive.

To disable them:

1. Open Avast

2. Go to Menu > Settings > Protection > Core Shields

3. Scroll to Configure shield settings

4. Under Web Shield, uncheck:

   • Enable HTTPS Scanning

   • Enable Reputation Services

Turning these off may reduce disk usage, especially on older or lower-end PCs.

Fix 8: Limit Avast Background Activity

You can configure Avast to use fewer system resources when you’re actively using your computer.

Steps:

1. Open Avast

2. Go to Settings > General > Performance

3. Find Smart Scan or Background activity

4. Enable the option to Limit background activity while you’re using your PC

This helps Avast run silently and reduce its impact while you’re working.

Fix 9: Perform a Clean Boot

A clean boot helps identify if other software is contributing to the high resource usage.

How to perform a clean boot:

1. Press Windows + R, type msconfig, and press Enter

2. In the Services tab, check Hide all Microsoft services

3. Click Disable all

4. Go to the Startup tab > Open Task Manager

5. Disable all startup apps

6. Restart your PC

After reboot, observe Task Manager to see if Avast still uses high CPU/disk. If not, another program may be conflicting with it.

Fix 10: Reinstall Avast

If none of the above methods work, a full reinstall can solve deeper issues.

Steps:

1. Go to Control Panel > Programs > Programs and Features

2. Uninstall Avast

3. Restart your PC

4. Download the latest version from the official Avast website

5. Reinstall and configure it carefully (disable unneeded features)

Bonus Tip: Consider an Alternative Lightweight Antivirus

If Avast continues to use excessive resources and disrupts your workflow, you might consider using a lighter antivirus program such as:

• Microsoft Defender (built into Windows)

• Bitdefender Free Edition

• Kaspersky Security Cloud Free

These options offer protection with minimal impact on performance.

Conclusion

High CPU and disk usage from Avast on Windows 10 or Windows 11 can be frustrating, but it’s usually fixable with the right configuration. From updating the program and disabling specific shields to adjusting scan frequency and performing a clean boot, the steps above should help you regain your system’s performance.

Quick Summary of Fixes:

• Update Avast

• Disable Cleanup Premium and unused shields

• Reduce scan frequency

• Repair or reinstall Avast

• Limit background activity

• Add exclusions in Windows Defender

• Consider switching to a lightweight antivirus

By following these steps, you can continue using Avast for protection—without sacrificing speed and performance.