Avast Antivirus is set to automatically update whenever new virus definitions or a new application version are available. We strongly recommend you keep these automatic updates enabled. It is also possible to perform manual updates, or prevent the application from downloading and installing updates without your permission.

This article explains how to manually update virus definitions and application version, as well as how to change the automatic update options.

Manually update virus definitions

Avast Antivirus uses a database of known virus definitions to identify malware and other threats on your PC. To manually check for and install updates to the virus definitions, follow the steps below:

1. Right-click the Avast icon in the notification area of your Windows taskbar and select Update ▸ Engine and virus definitions.
2. If your Avast Antivirus doesn't start checking for updates automatically, click Check for updates.
3. Wait while your Avast Antivirus checks for and installs virus definition updates.
4. When the update is complete, you see the status: Virus definitions are up to date.
5. You may need to restart your PC to complete the update. If prompted, click Restart now to immediately reboot your PC.

Manually update the application

Updates to the application version provide bug fixes and general improvements. Updating the Avast Antivirus application also updates the engine and virus definitions. To manually check for and install updates to the application and virus definitions, follow the steps below:

1. Right-click the Avast icon in the notification area of your Windows taskbar and select Update ▸ Program.
2. If your Avast Antivirus doesn't start checking for updates automatically, click Check for updates.
3. Wait while your Avast Antivirus checks for and installs application updates.
4. When the update is complete, you see the status message: Your application is up to date.
5. You may need to restart your PC to complete the update. If prompted, click Restart now to immediately reboot your PC.

Change virus definition update settings

1. Open Avast Antivirus and go to ☰ Menu ▸ Settings.
2. Select General ▸ Update.
3. In the virus definitions section, click More options.
4. Select your preferred option:
   • Automatic update (enabled by default): updates are downloaded and installed automatically on a regular basis. You may need to restart your PC to complete an update. If prompted, click Restart now to immediately reboot your PC.
   • Ask when an update is available: notifies you when new virus definitions are available. Your confirmation is required to complete the update.
   • Manual update (not recommended): updates are not automatically installed and you are not notified when new virus definitions are available.
   • Enable streaming update (enabled by default): downloads micro-updates continuously as new malware is discovered.
   

Change application update settings

1. Open Avast Antivirus and go to ☰ Menu ▸ Settings.
2. Select General ▸ Update.
3. In the application section, click More options.
4. Select your preferred option:
   • Automatic update (enabled by default): updates are regularly downloaded and installed. You may need to restart your PC to complete an update. If prompted, click Restart now to immediately reboot your PC.
   • Ask when update is downloaded: notifies you when application updates are downloaded. Your confirmation is required to complete the update.
   • Ask when an update is available: notifies you when application updates are available (before downloading). To receive the update, you need to start the download and installation process manually.
   • Manual update (not recommended): updates are not automatically installed and you are not notified when a new update is available.
   

Configure proxy settings

The proxy settings section is for users who connect to the internet through a proxy server. This section allows you to adjust your proxy settings to avoid issues with downloading virus definitions and application updates.

To configure proxy settings for application updates:

1. Open Avast Antivirus and go to ☰ Menu ▸ Settings.
2. Select General ▸ Update.
3. In the application section, click More options.
4. Tick the box next to Use specific proxy server and type your proxy details into the relevant text boxes.
   • Type: click the drop-down arrow and select HTTP or SOCKS v4.
   • Address: enter the address of your proxy server.
   • Type of authentication: if the proxy server requires authentication, specify the type and enter the Username and Password.