Best Free Antivirus Software

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To begin with let me say this: there is no best antivirus out there. Why do I say this? Any product that you take will behave differently against various virus samples since the AV engines and other components incorporated in them are of different technologies.

While one product might have higher detection ratio, another might have better malicious URL blocking or virtualization techniques, yet another might have lesser impact on system performance and so on.

Read more about Antivirus Engine and other related details at the end of this article.


Rated Products

Qihoo 360 Total Security  

This free antivirus is better than most commercial ones.

Our Rating: 
License: Free
  • Totally free, light on resources, extremely fast scan times and pre-configuration protection modes
  • Smooth running installer with no adware, pleasing UI and comes with many themes
  • Fast updates/fixes and excellent customer service with immediate replies
  • Great signatures with multiple engines and in-house cloud protection
  • Web protection addon, browsing locking, webcam, sandbox and usb protection modules
  • Online shopping protection, malicious URL protection and network threat blocking
  • Includes Glasswire Firewall and Windows patch-up components
  • Great detection rates, with very high zero day protection
  • Speedup and clean-up tools might not be for everyone (not present in Essentials version)
  • Bitdefender or Avira engines not enabled by default
  • Might encounter few false positives
  • PUP [Potentially Unwanted Programs] detection needs to improve
Read full review...

Avast Free Antivirus  

The only antivirus with a fully customizable installer and selection of user preference components.

Our Rating: 
License: Free (Limited features)
  • Extremely light on the system with a modern and clean UI
  • The only antivirus with a fully customizable installer, selection of user preference components
  • Works best in hardened or lock-down mode, which blocks all unknown programs (medium-expert users only)
  • Top notch detection capability, many secondary components to offer variety to a wholesome software
  • Excellent malicious URL blocking, network protection, outdated software checking, integrated password manager, and comes with a rescue disk.
  • Deep screen technology that includes Sandbox and Safe machine components for protection
  • Bloated default setup, some ads and pop'ups
  • Account creation for further protection after a month
  • Lack of an anti-ransomware module, and Deepscreen disabled by default
  • Cloud reputation, Malware signatures and HIPS module needs improvement
  • Offers Google Chrome and various bloated secondary components during install [Choose custom install]
Read full review...

Comodo Internet Security Premium  

Provides a multi-layered protection scheme with HIPS, sandbox, antivirus and firewall.

Our Rating: 
License: Free (Limited features)
  • Feature-rich with lots of options for customization along with setting tolerance against prompts
  • Tweaked settings gives the best 0-day protection among the pack
  • Multi-layered protection scheme with HIPS, Sandbox, Antivirus and Firewall
  • Industry grade firewall with options for learning and behavioural blocker
  • Low on resources with various graphical skins available and a clean user interface
  • Painful for beginners to use it, not very newbie friendly 
  • Av-module is a bit weak especially the signature based detection
  • Auto-sandboxing happens for various legitimate files, troubles with FPS games
  • Too many tweaks needed for better protection
  • Buggy software and updates are released slow.
  • Chromodo browser, Yahoo search engine, custom DNS and Geek Buddy offered during default install. [Click customize installation during install]
Read full review...

Avira Free Antivirus  

A free antivirus with high quality signatures, very fast updates and less false positives.

Our Rating: 
License: Free (Private/Educational use)
  • Pretty light on the system and runs smooth without system slow-downs
  • Clean ad-free GUI, Ad-free installer, No pop-ups or ads
  • High quality signatures, very fast updates, excellent detection on non-zero day threats
  • Deep file scans with very less false positives
  • Avira Protection Cloud makes for an excellent cloud engine
  • Browser safety Add-ons available for major browsers
  • Zero day protection (heuristic & behavioural shield) is very weak. 
  • Ineffective Browser launcher which is a memory hog (can be uninstalled)
  • Painful removal for detected files. Repeated scans from Luke Filewalker increases CPU & RAM usage. 
  • Multiple file exceptions needs to be added (real-time and on-demand)
  • No firewall/sandboxing/web shield technologies
Read full review...

Panda Free Antivirus  

Gives you antivirus protection with low memory and CPU usage, and collective intelligence cloud security.

Our Rating: 
License: Free (Private/Educational use)
  • Low memory & CPU usage thanks to cloud protection
  • Tiled UI with customizable interface and nicely rendered Settings interface
  • Collective intelligence cloud security - Downloading virus definitions is history
  • Good detection rates and behavioural analysis program
  • Fairly good web protection and hardware resource handling
  • Dependant on internet connection leading to weaker offline protection
  • Slow scanning speed, no fingerprinting (successive re-testing same files) and at times issues with virus removal
  • Not really light, performance impact in web browsing, installation and copying
  • Certain false positives despite the information available at cloud
  • Watch out for Panda security toolbar during install
Read full review...

Honorable Mention


Related Products and Links

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Antivirus Engine

It is used for Real Time malware protection of files and is the core component to scan data on your PC for detecting and removing malware from hard disk, memory, boot sectors, network drives, removable disks, or from external network traffic (internet).

  • How does an antivirus detect malware:

Firstly you got the signature-based detection which contains an offline database of known patterns of malware downloaded from the internet which can identify specific malware codes or family of malware. Then you have heuristic based detection that identifies pieces of code that are unlikely to be found in legitimate programs and hence is prone to false positives depending on the sensitivity of heuristics. Virtualization and sandboxing unpacks or executes unknown programs in an isolated secure environment so that their behaviour can be analysed and scanned using the antivirus engine. The latest one is cloud based detection that requires a reliable internet connection and sends the suspicious scanned file over the internet and the analysis is done by the vendors' machine running the cloud engine.

  • Scanning for viruses:

Most antiviruses include these basic scan types: On-demand scan/manual scan is initiated by the user from right click context menu or from within the software. On-access scan is initiated when the resource is being accessed like running an executable, copying files from external drives etc. Scheduled scan periodically ensures that the system is free from malware by setting the time and frequency for scanning. Startup scan/quick scan checks most important locations like running processes, startup items, system memory and services, boot sectors and so on.

To be Continued in the next update....... Firewall, Proactive protection, Web protection components and more.



This software category is maintained by volunteer editor George.J. Registered members can contact the editor with any comments or questions they might have by clicking here.

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Average: 4.3 (2172 votes)


While literally correct in this particular article, Rubenking does include a link (in the next-to-the-last paragraph) to an earlier review of MSE compared to other A-V freeware.

This piece merely discusses MSE's standing in various labs' tests, which has become something of a recent issue -- especially with Redmond. (As far as firewalls are concerned, one of MSE's features is its integration with the built-in Windows Firewall.)

Having said that, it would obviously have been more useful to many for Dennis Labs to have included other freeware in their evaluation of, and comparison to, MSE. Perhaps they will at some point in the future...

Thanks Wolfram.
Have you tried using the avira fusebundlegenerator to produce your files for manual upload?
I have experimented with it succesfully this week so far. It saves downloading large files every update. I only have a 1 MB "broadband" connection here in rural UK!!!!!!!!!
Thank you very much for your inputs - greatly appreciated. I have used the Avira 9 version you pointed out on my windows 7 laptop and it is very fast there too. Although I do still prefer good old XP for my hardworking Desktop faster and fewer overheads.

The answer to your question is "yes". But I avoided to tell you about AFG, because I thought you will find this option too complicated. And also because I wanted you to avoid any direct contact with Avira's servers. I'm sorry, I did not knew about your limited capacity Internet connection.

The main purpose of Avira Fusebundle Generator is to allow, to a Network Administrator, to update the Avira security products on workstations which are not connected to the Internet.-

Thanks Wolfram
I do build and repair PC and laptops and am reasonably IT savvy - happy to use regedit etc.
It was just the brutal and agressive way that Avira product update installed/failed to install and damaged other programs including windows system files that threw me and my first post was meant as a warning to others in case they too get caught out and to show that Ask toolbar "attacked" areas other than the registry and trying to remove it from Firefox was a pain.
No I'm not happy with Avira as a company but if I can update only a few kb instead of 80MB every day it helps big time.
Again thank you for your time and help in this issue - you are a credit to Gizmos

A warning about Avira 2013 and note to the editor.

I have used Avira free for 7 years in layered protection with Malwarebytes and microsoft security essentials. MBAM Sygate firewall and Avira as realtime and Msoft as on demand only - no problems other than Avira's stupid nag screens. No infections either.
BUT Avira updated itself last week from version 12 to version 13 and it completely stuffed the windows system.
well avira decided it is not compatible with MBAM, sygate firewall, windows firewall and Msoft securtiy essentials so decided to uninstall them without permission from me.It also installed Ask toolbars and search engines without permission in Firefox and IE8. It then failed to uninstall Avira 12 properly and couldn't install version 13.
When I rebooted the PC crashed BSOD.
Tried to remove Avira in safe mode - what a Bast**** took 4 goes 2 hours and a lot of know how to even get it part removed.
Downloaded Avira's own registry cleaner using a laptop as internet access was broken by the avira cock up
This registry cleaner failed so had to use unlocker in safe mode to kill the reg processes and regedit to get rid of them.
Booted back into windows and found that Avira had damaged several system 32 files and .dll files making a SFC scannow necessary to repair system 32 files then I had to use winsockfix as the TCP/IP software module had been trashed by Avira!!!!
Took another 2 hours to remove Ask and all of its components and again their own removal tool failed.Ask had removed all 5 of my usual search engines.Had to manually remove reg entries AND A FILE IT HAD PUT INTO FIREFOX PROFILES SEARCH ENGINES PLUG INS.Then reinstall "proper SAFE search engines"

Am I alone in this?
No see what the editor of CNET anti virus had almost identical issues.
So a warning don't update to Avira 13 if you have any other Anti virus installed or even if you removed it have any registry entries left as it waill crash your machine.
Avira have no interest in this and will not allow other anti virus sotware to run with it.
Given most experts agree that multii layered software is the best protection then this is an issue.
Sadly it seems that many other of the big AV systems are doing exactly the same thing and forcing you to install just their system with firewall, browser protection,anti phishing, cloud god knows what etc etc but not allowing any other AV software.
So you are stuffed if their engine or definitions doesn't have all up to date data!
If any one knows of a good realtime AV scanner with simple user controlled actions that allows single file scanning and is compatible with MBAM please post here.

Unfortunately, there are other Avira [Free] AV users who confronted themselves with similar situations. Volens-nolens, you received a lesson: you should have installed, on your PC, a "Backup and Disaster Recovery Software".

You can find some useful suggestions, in this respect, right here, on TechSupportAlert website:

There are other free "disk imaging" solutions, as well; provided by Macrium Software, EaseUS, Paragon Software, a.s.o.

In what concerns the AV, I would like to give you a helping hand - in the hypothesis that you are still using Windows XP:

If you have enough free time at your disposal, reinstall the Operating System. And then, if you like so much Avira's product, download and install Avira 9. You can find it at this URL:

Then you can download a valid license key, from here:

(On the above indicated webpage you have the dl. link and the updating instructions.)

Finally, if you want to update Avira's AV Free database, DO NOT use the automatic update service (in fact, I advise you to deactivate it). Always download the Virus Definition File from here:

Then proceed to Manual Update.

I understand why you like Avira AV: its resources consumption is low. And its protection is almost unbeatable. Unfortunately, starting with Avira AV 2010, this very good product began "to glide into bad habits".

But, before going back to Avira, maybe you would like to try, a little, Avast Free Antivirus 7. At least in what concerns its interface, you might remain impressed...

I hope this helps.-

Hi Wolfram
I did as you suggest but hit a problem that when I try to manually update from the fsbdev file Avira says that it cannot update as the license is no longer valid.
Do you have any suggestions as to how to get a valid license for this version as it is no longer supported?

Yes, I sure have. But I do not know if Gizmo will allow me to post a "direct download link" - for the "hbdev.key" file. Anyway, here it is:

http [ COLON ]//personal [ DOT ] avira-update [ DOT ] com/package/peclkey/win32/int/hbedv.key

If my post will be edited, here is what you can do:

In the above indicated link (, please read the post number 2 - belonging to Barrie. And follow, exactly, his instructions.

Important: you can NOT "manual update" the "hbdev.key" file! The Manual Update I was talking about it refers ONLY to the Avira Antivir Virus Definition File ( - downloadable from Softpedia.

Note: if you want to be allowed to delete the old "hbdev.key" file, you must make the following "maneuvers":

Open Avira Antivir Personal Free Antivirus main window. Then click on "Configuration". In Expert mode, click on General, expand, and select Security. Then uncheck both the options under Product Protection.

Now you can delete the old "hbdev.key". And replace it with the new one.
Your copy of Avira 9 Free should have a period of life prolonged up to 30.06.2013.

Now go back to Configuration menu, and check both the options from Product Protection. Then Re-start your machine.

And, voilà, now you have a fully functional Avira 9 AV!

I tested all these on someone else's PC and everything worked "like greased".

Good luck!

[Moderator's note : Link obfuscated. Please respect the rules of the site.]

Hi Wolfram
thanks - it worked and as you say just like the good old days - fast and clean. Just one problem the license runs out shortly - how cann it be extended if it is a non supported version now - I see the same question was asked on the forum link you provided ?

Well, I am quite sure that Avira will release a new hbedv.key file before that "expiration day". I noticed that they are doing this every six months, or so. As long as the newer versions of Avira AV will use the same old hbedv.key file, the "life" of Avira 9 will be maintained. The download link for this "vital" file will remain the same. But, I suppose you can manually update the program (its viruses definition file, I mean), even if its License has expired long time ago. I am glad that you have succeeded to set-up a fully functional machine. Try to always avoid the "Automatic Updates", if possible.-

thank you for your very helpful and well considered response.
I do have a back up system installed it is [commercial mention edited out] which whilst it is not freeware it is superb so I could get back to where I was a week or so before the Avira fiasco but of course things change in a week so I thought I could repair the system - which I did but it took some time! I could still go back to the old image but my point was the agressive way Avira behaved and how it installed and removed items without user permissions.
I did like Avira - as you say very light and pretty good detection and reasonable user control. I must say what they have done to it is needlessly agressive as well as ill thought out.
The same comments and problems apply to the paid for version if any one was thinking of trying that.
Thanks for the links to the old version and definitions updates I wasn't aware that they were available other than through automated download.
I have thought about Avast but heard some negatives abd was worried again about compatibility issues as this destroy competitors software seems to be becoming almost universal. I shall have another look given your very helpful comments.