Adjusting settings for Avast Antivirus scans

Avast Antivirus includes a range of manual antivirus scans to protect your PC against malware. While customizable settings are available for some predefined scans, we recommend you only modify settings for custom scans. For more information about antivirus scan types, read the following article:

Access scan settings

Manual scans are predefined antivirus scans that you can manage and schedule, for example, Full Virus Scan or Targeted Scan.

  1. Open the Avast Antivirus user interface and select ProtectionScans.
  2. Click Settings located under the scan tile you want to change settings for (Full Virus Scan or Targeted Scan).
    The Boot-Time Scan has different settings options. For more information about Boot-time scan, read the following article:
  3. Use the tabs on the left-side of the window to manage different aspects of your scan.

Custom scans enables you to create a new scan and define each of the parameters to suit your individual requirements.

  1. Open the Avast Antivirus user interface and select ProtectionScans.
  2. Click the Custom scans tile.
  3. Click the Create a New Scan tile to configure settings for your new scan, or click the gear icon next to a scan on the list and select Settings from the context menu to customize settings for your existing scan.
  4. Use the tabs on the left-side of the window to manage different aspects of your scan.

Specify a scan type

The Scan tab includes the following settings:

Scan name

Provide a name and description for your scan. If you are creating a custom scan, this information appears on the tile of your scan so that you can easily recognize it.

Scan areas

Use the drop-down menu to select the data space you want the scan to analyze. You can choose to scan any of the following areas:

  • Storage drives and removable media: the options in this section apply to data that is stored on physical devices such as hard disks and USB sticks.
  • Auto-start programs and modules loaded in memory: the options in this section apply to applications and processes that launch after system startup or run in the background.
  • Interactive selection: this option prompts you to specify a location on your PC each time you run the scan.

File types

You can configure your scan to analyze all files within the defined area by selecting Scan all files (slowest). Alternatively, configure your scan to only analyze files that are typically vulnerable to malware by selecting one of the following options:

  • Content (slow): the scan determines the format of each file according to its content, then scans the files identified as typically vulnerable to malware. This option is useful if file content differs from the extension type in the file name.
  • Name extension (fast): the scan analyzes only files with risky extension types in the file name, such as .exe, .com, .bat. Alternatively you can specify the extension types you want the scan to analyze by clicking Add. In this case, only the specified extension types are scanned.

Adjust scan sensitivity

The Sensitivity tab includes the following settings:


Heuristics enable Avast to detect unknown malware by analyzing code for commands which may indicate malicious intent.

Use the orange bars to indicate your preferred level of heuristic sensitivity. The default setting for new custom scans is Normal (three bars). With higher sensitivity, Avast is more likely to detect malware, but also more likely to make false-positive detections (incorrectly identify files as malware).

The following additional settings are also available:

  • Use code emulation: unpacks and tests any suspected malware in an emulated environment where the file cannot cause damage to your PC. This option is ticked by default for new custom scans.
  • Test whole files: enables the scan to analyze entire files rather than only the parts typically affected by malicious code. When this option is ticked, the scan is slower but more thorough.
  • Scan for potentially unwanted programs (PUPs): enables the scan to look for programs that are stealthily downloaded with other programs and typically perform unwanted activity.
  • Follow links during scan: enables Avast to scan other files used by the files being scanned for potentially harmful content. This option is ticked by default for new custom scans.

Select packers (archive formats) to be scanned

On the Packers tab, you can specify the compressed file types that you want Avast to unpack during the scan, for example, .zip and .rar files.

By default, Self-extracting archives, Droppers and NTFS streams are ticked for new custom scans. Other archive types do not need to be scanned because unless they are extracted, they cannot harm your PC. If you tick All packers, the scan analyzes all archive files, which significantly increases the scan duration.

Set up automatic scan actions

By default, Avast reports any suspicious files at the end of the scan and you can choose what to do with each one. On the Actions tab, you can specify an action to apply automatically during the scan when a threat is detected.

To view available options, tick Automatically apply actions during scan. Use the tabs to select a file type (Virus, PUP, or Suspicious), then use the drop-down menu to select an action:

  • Fix automatically: attempts to repair the file. If unsuccessful, moves the file to the Virus Chest or deletes the file if neither action is successful..
  • Move to Chest: sends the file to the Virus Chest where the file cannot harm your system.
  • Repair: removes malicious code if the file is only partially infected. This action is not possible if the entire code is malware.
  • Delete: permanently removes the file from your PC.
  • No action: makes no changes to the contents or location of the file (not recommended as an automatic action).

When you select an action, an additional drop-down menu appears. You can use the drop-down menu to apply an alternate action if the first action fails.


Specify rules to apply when a threat is detected inside an archive:

  • If necessary, perform the selected action at the next system restart (default option for new custom scans): applies actions when you next restart your PC, if the action requires it.
  • Try to remove only the packed file from the archive. If it fails, do nothing (default option for new custom scans): attempts to remove the contained file or program but does not delete the entire archive.
  • Try to remove only the packed file. If it fails, remove the whole containing archive: deletes the entire archive if unable to remove the file or program contained within.
  • Always remove the whole archive: deletes the entire archive.

Optimize scan performance

The following settings are available in Performance:

  • Scan priority: use the orange bars to indicate the scan's level of importance when other applications are running on your system.
  • Speed up scanning by using the persistent cache: enables the scan to refer to information retained from previously scanned files.
  • Store data about scanned files in the persistent cache: stores data about scanned files in your system's permanent memory so that future scans can refer to this data and run faster.
  • Speed up scanning by reading files in the order they are stored on disk: reduces the amount of time the scan takes to locate stored data by scanning files in the order that their physical data is stored on the disk (faster) rather than the order that the files are organized in the file system (slower).

Create a scan report file

For troubleshooting purposes, Avast Support may ask you to provide scan logs from the Packers tab. To create a report file, follow these steps:

  1. Tick the box next to Generate report file, and select a name and format (plain text ANSI, plain text Unicode, or XML) for your report file.
  2. Use the drop-down menu next to If file exists to specify one of the following options:
    • Append: adds new results to the end of the previous report.
    • Overwrite: replaces the previous report with new results.
  3. Use the tick boxes to define the contents of the report:
    • Infected items: files and areas of the scanned environment which are identified as containing malware. This option is ticked by default.
    • Hard errors: unexpected errors which require further investigation. This option is ticked by default.
    • Soft errors: minor errors such as a file being unable to be scanned because it was in use.
    • OK items: files and areas which were identified as being clean. Ticking this option results in very long reports.
    • Skipped items: files and areas which the scan did not check because of the scan settings.
  4. Click OK.

Report files are saved in one of the following locations:

  • Windows 10, Windows 8.1, Windows 8, Windows 7, or Windows Vista: C:\ProgramData\Avast Software\Avast\report
  • Windows XP: C:\Documents and Settings\All Users\Application Data\Avast Software\Avast\report

Exclude certain files from scanning

On the Exclusions tab, you can specify files or folders that you want the scan to ignore by creating an exclusion.

To add an exclusion, type its location manually into the text box or click Browse..., tick the relevant folder, then click OK. To add another location to the list, click Add. To remove a location, click the relevant row, then click Delete.

File and folder locations can include wildcard characters ? and *. The asterisk replaces zero or more characters, and the question mark replaces a single character. For example:

  • To exclude all HTML files, type *.htm* into the text box.
  • To exclude a folder and its sub-folders, add \* to the end of the folder name, for instance C:\example\* .
  • To exclude all files labeled in a certain way on any of your hard drives, include ?:\ in front of the path, for instance ?:\example.exe .

For more information about exclusions in Avast Antivirus, read the following article:

Schedule a scan

On the Scheduling tab, You can schedule a scan to begin at a time convenient for you. To schedule a scan, follow these steps:

  1. Select the Scheduling tab from the left panel and tick Schedule this scan.
  2. Specify if you want the scan to run on just one occasion (Once) or periodically (Daily, Weekly, or Monthly).
  3. Manage your preferences for the following options:
    • Do not start the scan if running on batteries: tick to ignore schedule settings if your PC is not connected to a power source.
    • Pause the scan if batteries mode begins: tick to pause the scan if your PC is removed from its power source during the scan.
    • Shut down the system after the scan finishes: tick to automatically turn off your PC after the scan.
  4. Set the time that you want the scan to run in 24-hour format (for example, instead of 3pm use 15:00).
  5. Specify the day that you want the scan to run.
  6. Click OK.
  • Avast Ultimate 18.x
  • Avast Premier 18.x
  • Avast Internet Security 18.x
  • Avast Pro Antivirus 18.x
  • Avast Free Antivirus 18.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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