Every Avast antivirus (Free Antivirus, Pro Antivirus, Internet Security, Premier), even the free version, offers a great feature which can search for any viruses and malware on your computer before it even starts. It’s called a Boot-Time Scan and below are the steps how to perform it in the latest 2017 version. It works great even with the latest Windows 10 release.

Technically boot-time scan runs before the Windows are loaded, so it doesn’t give malware any chance to hide itself. From our experience we recommend running full boot-time scan at least once a month, to make sure your computer is clean.

Quick Summary

  1. Open Avast interface and go to ‘Protection‘ » ‘Antivirus‘ » ‘Other scans
  2. Select ‘Boot-time Scan’ and click on ‘Run on next PC reboot’
  3. Restart your Windows and the boot-time scan will take place

Read more detailed steps and other options including screenshots below.

1. Schedule a Boot-Time Scan

Open interface of your program and navigate to tab ‘Protection‘ » ‘Antivirus‘ in the left menu. Once the scan overview appears click on ‘Other scans‘ option.

Running a Boot-time Scan in Avast 2017 – Scan Overview

Running a Boot-time Scan in Avast 2017 – Scan Overview

Once you are on the overview of other scans, click on ‘Boot-time Scan‘.

Running a Boot-time Scan in Avast 2017 – Other Scan Overview

Running a Boot-time Scan in Avast 2017 – Other Scan Overview

On the Boot-time Scan window click on ‘Install specialized definitions‘ to add special virus definitions which detects malware on inaccessible places for Windows. Once done click on the green button ‘RUN ON NEXT PC REBOOT‘ and you are set.

Running a Boot-time Scan in Avast 2017 – Boot-time Scan

Running a Boot-time Scan in Avast 2017 – Boot-time Scan

Also the message will change to ‘Scan will run on next boot‘. To cancel boot-time scan simply click on the ‘Cancel scheduled scan‘ link.

2. Advanced Settings of the Boot-Time Scan

For more advanced options click on cog-wheel icon in the Boot-time Scan tile on the Other Scans overview (second screenshot in this article). In the boot-time scan settings you can select following options:

  • Areas to scan – All hard disks, only system drive, or auto-start programs
  • Heuristics sensitivity (analysis which detects not yet known viruses) – Off, low, normal, high (recommended though it may increase amount of false-positives found)
  • What do to do if a threat is found – Ask, move to chest, repair, delete, no action, or fix automatically
  • Others – Scan for potentially unwanted programs (PUPs), unpack archive files

Changing any of the settings or just confirming doesn’t make the boot-time scan scheduled. You still need to perform the steps above.

Running a Boot-time Scan in Avast 2017 – Boot-time Scan Settings

Running a Boot-time Scan in Avast 2017 – Boot-time Scan Settings

Please note the boot-time scan isn’t happening in Windows but before Windows are loaded. Below you can see the example of how the boot-time scan looks in the Avast antivirus 2016.

Running a Boot-time Scan in Avast 2017 – Boot-time Scan In Progress

Running a Boot-time Scan in Avast 2017 – Boot-time Scan In Progress

Your Windows will boot automatically if there is no virus found. If Avast founds a virus, you can perform one of the actions below by pressing a relevant number on your keyboard

  • 1 – Fix automatically
  • 2 – Fix all automatically
  • 3 – Move to Chest
  • 4 – Move all to Chest
  • 5 – Delete
  • 6 – Delete all
  • 7 – Repair
  • 8 – Repair all
  • 9 – Ignore
  • 0 – Ignore all

If the infected file is in the folder you also need to confirm the action by pressing

  • 1 – Yes
  • 2 – Yes all
  • 3 – No

You can always press ‘Esc‘ key to cancel the scan and continue with the boot. After the boot-time scan is complete, you can find it’s report in ‘Scan‘ » ‘Scan for viruses‘ » ‘Scan history‘. Alternatively you can navigate to report by going to ‘C:\ProgramData\AVAST Software\Avast\report\aswBoot.txt‘.

Additional Notes

Although we have used Avast Free Antivirus 2017 screenshots in this article, these steps are also applicable for all Avast Antivirus solutions (i.e. also for Avast Pro Antivirus, Avast Internet Security, or Avast Premier) running the latest version available.

Steps are relevant for all Windows versions – Windows XP, Windows Vista, Windows 7, Windows 8, Windows 8.1 and Windows 10 (including Anniversary Update).

Written by Paul B.

My name is Paul and I love Avast since the Home Edition v4.8 (2008). I am recommending it to all my friends, but I realized they don't know how to use it. So I started this site in order to help others getting maximum from this awesome antivirus. Feel free to contact me via Facebook, comments below or this form.

This article has 34 comments | Did we miss anything? Just let us know in the comments!

  1. John Reply

    Does anyone know why “Scan History” does not show boot scans on Windows 10?

  2. Techy Jen Reply

    Boot time scan is under “protection”, “antivirus”, “other scans”, then “boot time scan”. It’s not that easy to find anymore but it’s still there. Hope that helps those unable to locate it.

    • Paul B. Reply

      Thank you for your comment. We have just updated the article to be relevant for the latest 2017 version of Avast.

  3. Ron Reply

    April 2017…no boot time scan found on the latest version. wish they would stop slowly stripping this software and adding in pop ups trying to get me to buy more services. Very unfortunate because this used to be really great antivirus…

  4. Mitr Reply

    Hello, Paul B. , Most of the complaints put up here appear to be the result of unattended “Scan Settings”, same thing happened to me too. But when I set right “scan settings” at Boot Time Scan, all worries are resolved.

    Happy Antivirusing 🙂

    Some times it said 40MB file needed to be downloaded to perform Boot-Time-Scan and thereafter it annoyingly repeatedly asked whether to shut down pc. This appears area for improvement.

    One more question? Why use of Orange colour is profoundly used? If it is co-related to any/some religion, or Political thinking such as extreme Right, then others may be averse to use it. “Unbiased” coloured products/services attract more customer. 🙂
    Regards

  5. DARREN Reply

    Just downloaded the latest free avast and no boot time scan to be found anywhere!!

  6. Chris Rochester Reply

    Ran avast boot scan for first time on windows xp desktop. On boot up it said that it would take a long time to run so I chose escape. Computer is now hung up on Windows start up. Tried booting on safety mode and last successful start up mode. No luck. My computer is now useless. How can I get it back

  7. Daniel Reply

    I runned the boot-time scan..it starts and works for like 2 minutes then the system starts and the scan is cancelled..wtf,why the system starts from itself after 2 minutes of boot-time scan..?

  8. Anthony Odubiyi Reply

    I ran a boot scan on avast 2016 and it has taken over 2 day and it still going who much longer do I need to wait for it to finish?

  9. Jay Miller Reply

    I am running Windows 7 on an Acer pc. I used to be able to run the boot scan, but it does not show up anymore. Do I need to upgrade Avast or can I still use the free version and still get the “boot scan”.

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