Troubleshooting

• Enable rootkit scan on system startup: scans for rootkits when you boot your PC, before most applications and services are loaded. This option is enabled by default to ensure maximum protection. Unticking this option may slightly speed up startup but weaken your antivirus protection.
• Enable anti-rootkit monitor: enables Avast to monitor hidden malicious threats in the system. Unticking this option may resolve potential compatibilty issues that can cause system crashes. This option is enabled by default.
• Enable anti-exploit module: enables Avast to detect and block attempts to run malicious threads or processes in the memory. Unticking this option may resolve potential compatibilty issues that can cause system crashes. This option is enabled by default.
• Enable raw disk access during Avast boot-time scan: enables Avast boot-time scan to access and scan entire disk space, including dropped files and file fragments that may contain malicious code. This option is enabled by default. Unticking this option may slightly speed up boot-time scans but weaken your antivirus protection.
• Skip checking of digital signatures of infected files: enables Avast to report all files as suspicious even if they are from trusted publishers, which can speed up the scanning process. However, this option is disabled by default to avoid false positive detections which ensures that trusted files with valid digital signatures are not identified as malware and consequently deleted.
• Enable Avast self-defense module: prevents all critical Avast Antivirus files from being modified or deleted. This option is enabled by default. Unticking this option may enable attackers to modify or delete antivirus files to disable your antivirus protection and infect your PC.
  Note: Only untick temporarily at the request of Avast Support representatives for specific troubleshooting purposes.
• Load Avast services only after loading other system services: delays Avast Antivirus from loading until all other system services are loaded which can speed up the PC startup process but simultaneously makes your system temporarily unsecured against malware. This option is disabled by default to allow Avast services to load in the beginning of the startup process which ensures the full security of your PC.
• Limit program access for Guest account: restricts guest users (secondary accounts logged in to your PC) from accessing or modifying your Avast settings. This option is enabled by default to ensure only authorized users have this permission. Unticking this option allows all users (accounts) to access or modify settings.
• Enable hardware-assisted virtualization: improves the performance of virtualization. Avast uses hardware virtualization in anti-rootkit, Sandbox, self-defense, and CyberCapture components. This option is ticked by default. If Avast detects another virtualization software on your PC, it automatically disables this option. If Avast is not able to recognize virtualization software installed on your PC, and you encounter performance or compatibility issues, we recommend temporarily unticking this option.
• Use nested virtualization: allows other machine virtualization software (hypervisor) to cooperate with Avast virtualization, when possible. This option is enabled and visible only if other hypervisor is installed.

Passive Mode disables all active protection, such as Core Shields and Firewall, so that you can use more than one antivirus program at a time without interfering with the performance of your PC or the reliability of antivirus detections. In Passive Mode, Avast receives all virus definition and program updates which allow you to manually run scans to check for issues on your PC, however Avast does not actively protect you.

This feature is disabled by default, unless you install Avast on a PC with another antivirus program installed. To manually activate Passive Mode, click the red slider so that it changes to green. Then, click OK and Restart now to confirm your changes.

If you want Avast Antivirus to actively protect you from malware and other security threats, ensure that Passive Mode is turned off and the following conditions are met:

• All third party antivirus programs are uninstalled.
• The main screen of Avast Antivirus displays the text You are protected.

Note: If Avast is the only antivirus software installed on your PC, only activate Passive Mode temporarily for specific troubleshooting purposes.

For troubleshooting purposes, you may want to restore your Avast Antivirus settings to the original values. Follow these steps to restore Avast Antivirus default settings:

1. Tick the following option(s) to select the set of settings you want to restore:
   • Program settings (including default scans): refers to all program settings except antivirus shield settings.
   • Shield settings: refers to antivirus shield settings only. Modifying shield settings may affect your protection status.
2. Click Reset now to restore your settings.

Reset now removes all of your custom settings. This action cannot be undone.

Note: You can back up your settings in ☰ Menu ▸ Settings ▸ General ▸ Back up settings before you restore factory defaults. Read more...

If you experience issues sending or receiving emails when using Mail Shield with an email client (such as Microsoft Outlook or Mozilla Thunderbird), you can troubleshoot by specifying the ports used by your email provider in the Mail section.

By default, standard port numbers are specified for each protocol as listed below:

SMTP port(s):	25,857	Secure port(s):	465
POP port(s):	110	Secure port(s):	995
IMAP port(s):	143	Secure port(s):	993
NNTP port(s):	119	Secure port(s):	563

If you or your email provider use different ports, type them into the text boxes next to the appropriate protocols to ensure that your emails are monitored by Avast. Use commas to separate multiple port numbers.

In the Ignored addresses text box, type the addresses of any servers or ports that you want to exclude from scanning, for example, smtp.example.com. If necessary, separate multiple addresses with commas.

When ticked, the Ignore local communication option prevents Avast from scanning internal system communication between applications running on your PC. This option is ticked by default. Unticking this option configures Avast to scan all email communication, which increases security but may slow down the performance of your system.