avast! Free Antivirus on-demand scan

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avast! Free Antivirus on-demand scan

In this tutorial: How to run an on-demand antivirus scan or scan just one file or folder with avast! Free Antivirus in Windows XP, Windows Vista, Windows 7 or Windows 8

Last modified: 2012-04-14 21:42:08 EEST

Despite daily and monthly scheduled scanning, you might need to scan your computer in case you have any doubts. You can either scan just one file or folder or perform any default or custom scan whenever you need to.

Scanning just one file or folder takes less time, but to be really sure your computer is not infected you might need to perform a full scan.

Scanning just one file or folder with avast! Free Antivirus

To scan just one file or folder (aka directory), right-click the item in Windows Explorer and select Scan <item name>. You can also select multiple items using Shift or Ctrl keys if you need to!
avast! Free Antivirus, right-click menu on an item. To scan one file or folder, select Scan.

avast! Free Antivirus then scans the item(s) and if everything is okay, you will see a green "No threat found" message. Click Close.
avast! Free Antivirus Scan, No threat found. Click Close.

In case infected items were detected, you will see a red "Threat detected" message after the scan is complete. Click Show Results button.
avast! Free Antivirus - scanning just one item, threat detected. Click Show Results button.

An avast! Scan Results window opens with a list of all detected items. The default action is "Move to Chest" and this suits fine. Click the Apply button.
Please note that sometimes avast! real-time protection engine has already removed the infection(s) and the Apply button is grayed out. In case you are unable to click the button, don't worry - the threats have already been removed.
avast! Free Antivirus, Scan Results. Click Apply button to move all detected items to Virus Chest.

Cleaning might take up to several minutes.
As avast! Free Antivirus does not support removing individual files from all kinds of archives, you might encounter an error named "the operation is not supported for this type of archive". In such case ignore the error and either delete the archive file or run a Malwarebytes' Anti-Malware scan on the file immediately after closing the avast! Scan Results window.
Close the window by clicking the red X mark in the upper right corner.
avast! Free Antivirus - scan results window. For some packed files an error could occur - the operation is not supported for this type of archive. Ignore the error now and close the scan results window.

Performing a predefined or custom scan with avast! Free Antivirus

If you want to run a more thorough scan, open avast! Free Antivirus by clicking its orange ball-shaped icon in Taskbar Notification area.
If you stop mouse pointer on avast! Free Antivirus icon, your system status will be displayed. Normally this is "Your system is secured".

Click Scan Computer tab, open Scan Now and then find the scan you want to perform. Click Start button to the right of the scan.
avast! Free Antivirus, Scan Computer, Scan Now. To perform an on-demand scan, find the scan type you want to run and click Start button to the right of it.

The scan starts. As checking for viruses and malware can slow your computer down, you can pause scanning if you need to by clicking Pause button. To continue scanning, click Resume button. The Stop button is only for emergencies...
avast! Free Antivirus, Scan running. To pause a scan, click Pause button. To resume the virus check, click Resume.

If a scan finishes without detections, a green "No threat found" message appears. You can click OK button then and close avast! Free Antivirus main window using keyboard shortcut Alt+F4.
avast! Free Antivirus, Scan complete, no threat found. Click OK button.

If some virus or malware was detected, you will see a red "Threat detected" message after the scan is complete. Click Show Results button.
avast! Free Antivirus, Scan complete, threat detected. Click Show Results button.

avast! Scan Results window opens with default action for detected items set to "Move to Chest". This is fine, click Apply.
avast! Free Antivirus, Scan Results. Click Apply button to move all detected items to Virus Chest.

"Action successful" is displayed after each removed threat. Click Close.
There might be cases when a virus-infected file has already been deleted by avast! File Scanner or Windows Defender (in Windows Vista or 7). You will see an error message "The system cannot find the file specified (2)" then. This is not a problem, as the infected file has already been removed or moved to Virus Chest.

If avast! Antivirus has also detected a virus in operating memory, it will display the following information message and offer to perform a boot-time scan to remove the nasty virus. Always click Yes here and, otherwise your computer might stay infected! This will restart your computer and trigger a lengthy boot-time scan to remove the infection.
avast! Free Antivirus messages - avast! has detected a virus in the operating memory, do you want to schedule the boot-time scan and restart the computer. In such cases, always click Yes.

Read the avast! Free Antivirus boot-time scan article for more information about boot-time scanning and errors that might occur.

For really nasty rootkits that avast! Free Antivirus or Malwarebytes' Anti-Malware are not able to detect or remove, using ComboFix might be a good idea.