Adjusting settings for Avast Antivirus shields

Avast Antivirus shields actively analyze suspicious information coming and going from your PC, as well as potentially malicious content stored within it. These components detect and block malicious files, dangerous websites, unauthorized connections, and other threats.

For information about the settings for each Antivirus shield, refer to the following sections.

Default settings are optimal for most systems, so we do not recommend to make changes unless you find that there is a problem.

Turn a shield on or off

To enable or disable a shield, follow these steps:

  1. Open the Avast user interface and go to SettingsComponents.
  2. Click the ON/OFF slider next to the relevant shield:
    • To disable a shield, click the green slider (ON) and select how long you want to disable the shield for (10 minutes, 1 hour, until you restart your PC, or permanently).
    • To enable a shield, click the red slider (OFF) so that it changes to green (ON).

You can also enable/disable all shields, Firewall, and Real Site at once from the system tray. Right-click the Avast system tray icon and select Avast shields control, then select an action from the context menu.

We strongly recommend you keep all crucial security components, such as Antivirus shields and Firewall, enabled to ensure your maximum protection. We do not recommend turning off these components indefinitely by selecting the Stop permanently or Disable permanently options.

File System Shield settings

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

To modify your File System Shield settings, open the Avast user interface, go to SettingsComponents, and click Customize next to File System Shield. The following settings are available from the left panel:

  • Scan when executing: specify whether you want File System Shield to scan programs, scripts, or libraries each time they are run.
  • Scan when opening: specify which file types you want File System Shield to scan each time the files are opened.
  • Scan when writing: specify the file types you want File System Shield to scan while the files are being created or modified.
  • Scan when attaching: specify the file types you want File System Shield to scan on removable media devices (such as USBs or DVDs).
  • Exclusions: specify files or folders that you want File System Shield to ignore.
  • Advanced: manage scan settings which affect your system performance and scan accuracy.
  • Actions: specify files or folders that you want File System Shield to ignore.
  • Packers: indicate the compressed file types that you want File System Shield to unpack when checking for malware.
  • Sensitivity: adjust the heuristics analysis for detecting unknown malware.
  • Report file: specify whether you want File System Shield to produce reports of scan results.

Behavior Shield settings

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

To modify your Behavior Shield settings, open the Avast user interface, go to SettingsComponents, and click Customize next to Behavior Shield. The following settings are available from the left panel:

  • Main settings: specify which action to take if a threat is detected.
  • Exclusions: specify folders that you want Behavior Shield to exclude from scanning.

Mail Shield settings

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.

To modify your Mail Shield settings, open the Avast user interface, go to SettingsComponents, and click Customize next to Mail Shield. The following settings are available from the left panel:

  • Main settings: specify which types of messages are scanned by Mail Shield – inbound, outbound, or newsgroup messages. We strongly recommend you enable scanning for all email types to ensure your full security.
  • Behavior: enable or disable Avast email signatures that inform both you and recipients of clean or infected emails. Additionally, you can manage what actions occur during scans, and configure options for Microsoft Outlook.
  • SSL scanning: enable or disable scanning of emails sent or received using SSL/TLS encrypted connection. For some mail clients, this feature requires you to export a certificate from the SSL Scanning screen then import the certificate into your mail client's certificate store.
  • Actions: configure automatic responses to detected threats.
  • Packers: indicate the compressed file types that you want Mail Shield to unpack when checking for malware.
  • Sensitivity: adjust the heuristics analysis for detecting unknown malware.
  • Report file: specify whether you want Mail Shield to produce reports of scan results.

Web Shield settings

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

To modify your Web Shield settings, open the Avast user interface, go to SettingsComponents, and click Customize next to Web Shield. The following settings are available from the left panel:

  • Main settings: manage use of web scanning, script scanning and HTTPS scanning, as well as other functions which can increase scan speed and accuracy.
  • Web scanning: specify which type of content is scanned.
  • Exclusions: specify URLs, MIME types (mail extension types), or processes to exclude from scanning. This is useful when you download many files from a single, trusted source.
  • Actions: configure automatic responses to online threats detected by Web Shield.
  • Packers: indicate the compressed file types that you want Web Shield to unpack when checking for malware.
  • Sensitivity: adjust the heuristics analysis for detecting unknown malware.
  • Site blocking: allows you to block access to specific websites.
  • Script scanning: select the browsers you want Web Shield to block malicious scripts from. This includes remote threats from the web and outside sources, and local threats saved to disk or in the browser cache. Script scanning can also detect and block malicious scripts that come from HTTPS (encrypted) connections.
  • Script exclusions: specify the addresses of websites you want to exclude from script scanning. You may want to exclude specific web addresses so you can access all content on those sites. Tick the box and then enter the URL address you want to exclude. Use exclusions only if you are sure the website you want to exclude from scanning is safe.
  • Report file: specify whether you want Web Shield to produce reports of scan results.
  • Avast Ultimate 17.x
  • Avast Premier 17.x
  • Avast Internet Security 17.x
  • Avast Pro Antivirus 17.x
  • Avast Free Antivirus 17.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
  • Microsoft Windows Vista Home Basic / Home Premium / Business / Enterprise / Ultimate - Service Pack 2, 32 / 64-bit
  • Microsoft Windows XP Home / Professional / Media Center Edition - Service Pack 3, 32-bit

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