Adjusting settings for Avast Antivirus Core Shields

Core Shields are the main protection components in Avast Antivirus. The Core Shields are: File Shield, Behavior Shield, Web Shield, and Mail Shield. Refer to the sections in this article to manage the settings of your Avast Antivirus Core Shields.

Enable or disable all Core Shields

All Core Shields are enabled by default for your protection, but they can be instantly disabled for troubleshooting purposes. To temporarily disable all Core Shields:

  1. Open Avast Antivirus and go to MenuSettings.
  2. Select ProtectionCore Shields.
  3. Click the green (ON) slider, then select a time duration to disable Core Shields.
We do not recommend selecting Stop indefinitely.
  1. Click OK, Stop.

All Core Shields are now temporarily disabled. The Core Shields automatically enable again when the specified time duration elapses. To manually enable all Core Shields, follow steps 1-2 above, then click the red (OFF) slider so that it changes to green (ON).

Adjust sensitivity

You can change the sensitivity of the Core Shields from the default Medium sensitivity. High sensitivity increases the protection and potential for false positive malware detections. Low sensitivity reduces the chance of false positive detections, but may also reduce the effectiveness of the Core Shields. To change the sensitivity of your Core Shields:

  • Click and hold the white marker, then slide it to your desired sensitivity setting.

Configure behavior settings

Specify what you want the Core Shields to do when they detect viruses and potentially unwanted programs (PUPs).

  1. Select either the Viruses tab or the Potentially unwanted programs tab.
  2. Select your preferred option:
    • Fix automatically (recommended): The automatic fix tries to repair the file. If repair is not possible, the file moves to the Virus Chest. If that fails, the file is deleted from your PC.
    • Ask: You are prompted to decide what to do each time a threat is detected.
    • Ignore potentially unwanted programs: The Core Shields won't scan for these types of threats.

Additional behavior settings

Optionally tick (enable) or untick (disable) the following additional behavior settings:

  1. Enable CyberCapture Technology: An additional protection that analyzes unrecognized files.
    • Always block a threat: Blocks all threats automatically.
    • Ask me about decision: You are prompted to decide what to do each time a threat is detected.
  2. Enable Hardened Mode: Recommended for inexperienced computer users who want to really secure their PC. Hardened Mode uses information based on reputation services to determine which executable files are safe to open.
  3. Enable Rootkit detection: Monitors hidden malicious threats in your system. Unticking this option may resolve potential compatibility issues that can cause system crashes.
  4. Enable Exploit detection: Detect and block attempts to run malicious threats or processes in the system memory that can exploit vulnerable applications on your PC. Unticking this option may result in potential compatibility issues that can cause system crashes.

Manage individual shield settings

File Shield actively scans all programs and files on your hard drive as they are opened, run, modified, and saved. If malware is detected, File Shield prevents the program or file from infecting your PC.

Select the File Shield tab, then optionally tick (enable) or untick (disable) the following settings:

  1. Enable File Shield: Scans any file added to or opened on your PC. To temporarily disable File Shield, untick the box, then select a time duration. File Shield automatically enables again when the specified time duration elapses.
  2. Scan auto-run items when removable media is attached: Scans files that are programed to run automatically from removable drives (for example, a USB key) when they are connected to your PC.
  3. Choose file types to scan:
    • Scan recommended extensions: Only scans file types recommended by Avast.
    • Scan all files: Scans all file types.
  4. Scan programs when executing: Scans programs, scripts, and libraries each time they are run.
  5. Scan files when opening: Scans each time you open a file.
  6. Scan files when writing: Scans when files are being created or modified.
  7. Generate report file: Automatically generates reports of scan results.

Behavior Shield monitors programs installed on your PC for suspicious behavior that may indicate the presence of malicious code.

Select the Behavior Shield tab, then optionally tick (enable) or untick (disable) the following settings:

  1. Enable Behavior Shield: Warns you if any application behaves suspiciously. To temporarily disable Behavior Shield, untick the box, then select a time duration. Behavior Shield automatically enables again when the specified time duration elapses.
  2. Generate report file: Automatically generates reports of scan results.

Web Shield actively scans data that is transferred when you browse the internet to prevent malware from being downloaded and run on your PC.

Select the Web Shield tab, then optionally tick (enable) or untick (disable) the following settings:

  1. Enable Web Shield: Blocks web attacks & unsafe downloads. To temporarily disable Web Shield, untick the box, then select a time duration. Web Shield automatically enables again when the specified time duration elapses.
  2. Enable HTTPS scanning: Includes scanning of encrypted websites.
  3. Enable QUIC/HTTP3 scanning: Scans communications sent and received via Google's QUIC protocol.
  4. Block botnet attacks: Prevents botnets from using your computer to attack other computers.
  5. Enable Script scanning: Prevents browsers and other applications from running potentially malicious scripts. This includes remote threats from the web and outside sources.
  6. Enable site blocking: Allows you to block access to specific websites. To block access to a website from your PC, click Show Blocked WebsitesAdd Website, then enter the website address. Click Close to confirm the addition and return to Web Shield settings.
  7. Generate report file: Automatically generates reports of scan results.

Mail Shield scans for threats in your incoming and outgoing email messages. Scanning applies only to messages sent or received using mail management software, such as Microsoft Outlook or Mozilla Thunderbird.

Select the Mail Shield tab, then optionally tick (enable) or untick (disable) the following settings:

  1. Enable Mail Shield: Blocks dangerous email attachments. To temporarily disable Mail Shield, untick the box, then select a time duration. Mail Shield automatically enables again when the specified time duration elapses.
  2. Scan inbound emails (POP3, IMAP4): Scans all incoming emails sent using an SSL/TLS encrypted connection.
  3. Scan outbound emails (SMTP): Scans all outbound emails sent using an SSL/TLS encrypted connection.
  4. Add a signature to the end of sent emails: Includes a message for the recipient in an outgoing email confirming that the email has been scanned for malware and is clean.
  5. Mark in subject of mail containing a virus: Specify a specific word or phrase in the text box that will automatically be added to the subject of any email containing a virus.
  6. Scan attachment when attaching (Microsoft Outlook only): Scan outgoing email attachments sent with Microsoft Outlook.
  7. Generate report file: Automatically generates reports of scan results.

Further recommendations

For information about advanced settings for each of the Core Shields, refer to the following article:

  • Avast Free Antivirus 20.x
  • Avast Premium Security 20.x
  • Avast Omni 1.x
  • Microsoft Windows 10 Home / Pro / Enterprise / Education - 32 / 64-bit
  • Microsoft Windows 8.1 / Pro / Enterprise - 32 / 64-bit
  • Microsoft Windows 8 / Pro / Enterprise - 32 / 64-bit
  • Microsoft Windows 7 Home Basic / Home Premium / Professional / Enterprise / Ultimate - Service Pack 1, 32 / 64-bit

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