How-To Geek

How to Scan Your Computer With Multiple Antivirus Programs


You should only run a single antivirus application at a time, but none of them are perfect. Some antiviruses may catch malware that other antiviruses miss. Luckily, you don’t just have to rely on a single antivirus program.

The key to using multiple antivirus programs is running a single antivirus as your main background protection and running another scanner occasionally – say, once a week – for a second opinion.

If you have a suspicious file, you can also quickly scan it with in 46 different antivirus programs at once using a website.

Why You Shouldn’t Run Multiple Antivirus Programs At Once

Most antivirus programs are designed to be the single security solution for your computer. The antivirus has a background, always-on scanning feature that’s enabled by default. When you download a file, load a program, or access a website, the antivirus keeps an eye on everything and ensures it doesn’t match a known threat.

This works fine as long as you only have a single antivirus running at a time. These programs hook deep into your Windows operating system and are not designed to work together. In a best case scenario, running multiple antivirus programs at once could result in degraded performance. In a worst case scenario, the programs could interfere with each other and cause system crashes.

Read More: HTG Explains: How Antivirus Software Works


How You Can Scan Your Computer With Multiple Antivirus Programs

However, no antivirus program is perfect. Some antivirus programs may miss problems other antivirus programs will detect. To get more complete detection coverage, you may want to scan your computer with additional antivirus programs while leaving a single antivirus program – such as Microsoft Security Essentials (known as Windows Defender in Windows 8) — running in the background.

The additional antivirus programs you’ll use won’t stay running in the background. They’ll scan your computer once and give you a second opinion. You can load up the additional programs and scan your computer once a week with them. While running the manual scanner, you should consider disabling real-time protection in your primary antivirus program – if only to speed things up.

When you select an additional antivirus program, look for one that doesn’t stay running in the background – this feature is referred to by many names, such as real-time protection, on-access scanning, background protection, or resident shield.

There are several options for second-opinion scanning, including:

  • Malwarebytes: The free version must be started for a manual scan and can’t run in the background, which is perfect for this use case.
  • ESET Online Scanner: A quick, one-time scanner from the creators of NOD32. Unlike many online-scanning products from antivirus companies, ESET Online Scanner includes the ability to remove malware it finds.


When looking for a second-opinion antivirus, try to avoid the more lightweight options. Some products, such as Bitdefender QuickScan, may do a very quick scan that won’t necessarily find some malware. Bitdefender QuickScan and other products like it don’t remove malware they find, either – they exist to point you towards the company’s paid product.

Scanning a File With Many Antivirus Programs

If you have a suspicious file – perhaps you just downloaded it and are a bit worried or your antivirus says it’s malicious but the creator insists that your antivirus is offering up a false positive and the file is actually completely safe – you may want to scan that specific file with a variety of different antivirus programs.

Unfortunately, this can be difficult when you don’t have twenty different antivirus engines on your computer. Even if you did, updating each with the latest virus definitions would be way too much work.

When you need to scan a suspicious file in multiple antivirus programs, use the VirusTotal website – now owned by Google. You can upload files up to 32MB in size or even point VirusTotal at a URL online where it can download a file to analyze. The file will be scanned by 46 different antivirus programs on VirusTotal’s servers and you’ll see a report.


As with all antivirus programs, there’s no guarantee that the results are perfect. A file could be considered clean by every antivirus program but still be malicious. It’s also theoretically possible (although very unlikely) that a false positive could be marked as such by many different antiviruses. However, in practice, VirusTotal will tell you what a wide variety of antivirus programs think of a file, which can help you make a more informed decision about it.

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 01/16/13

Comments (23)

  1. MrCuddles

    What about installing 2 AVs and turn the backround scanner off.

    I have both AVG and AVAST Free working together. Sadly you cant turn off the AVG Services completely, even if you deactivate it in the options.

  2. gyffes

    I’m tech support for many who work in/around/with a local hospital; the hospital requires AV on any machine going on their network (they’ve exempted phones for now), so I put ClamAVx on the Macs: nice, light, only fires up when files are added to locations I tell it to watch.

    Unfortunately, Clam returns a fair number of false-postives, so I have to send the files to an online scanner for second-checking. I’m a big fan of VirusTotal for its speed and file-size limit.

    Mr. Cuddles.. try something like an active AV and pair it with something like ThreatFire, which doesn’t look for virus signatures so much as virus BEHAVIORS. Dual-layer protection and possibly more effective as it’ll likely spot new viruses by behavior (“hey, watch out, something is trying to change a file over here!”) long before the AV signature list gets updated.

  3. krish

    Hi, i feel all the anti virus providers spread some phobia in net users and sell their premium products for high prices.I feel there is no 100% perfect anti virus software as many new viruses are added to list every moment.Some anti virus programs slow down the system while updating data base it is difficult to open sites also at that time.An anti virus software with minimum security is enough for home users

  4. Rob

    Good article. I also use Malwarebytes, and have found it very useful in the past I use it about once a week, in addition to MSE. Also scan regularly with Spybot which is also recommended.

  5. Jim

    I don’t think ThreatFire is a good suggestion. PC Tools discontinued it quite some time ago. From their website – “PC Tools ThreatFire™ has been retired as a standalone product.”

  6. Shieldwolf2012

    I ran Trend Micro premium for years, eventually they just became a huge resource hog, So I discontinued them and now have Avast premium and Malewarebytes premium running side by side. with no appreciable drag on my CPU, each will find something the other doesn’t. When I run a scheduled full system scan (which takes a good 7-8 hours for all drives I use one or the other, generally the Avast. Also online i have WOT on my Chrome browser, and for the most part take their advice. I have only been infected once many years ago. (Knock on wood) I also follow basic rules and stay away from obvious scam sites. my Yahho mail also does a good jo scanning any attachments i might want to d/l

  7. Ron

    I use MalewareBytes and AVG on most 4 different computers and recommend the combination every chance I get. The combination, along with MSE, seems to do a great job of defending my computers.

  8. Richard Steven Hack

    It’s unfortunate that ThreatFire has been retired, however it still provides a degree of “active protection” which might be useful in addition to one main AV and one or more stand-by programs like MalwareBytes Antimalware and Superantispyware which do not offer such protection..

    Another product intended to work along with AV is Spyware Terminator. I’ve had issues with that product in the past at a client site, however. It seriously slowed the machines causing high CPU spikes when run with Kaspersky AV. However, I have not tested the current version for that behavior so it may be better now.

    Recent tests of Microsoft Security Essentials by two of the main antivirus test companies indicate that it is not as good as other products at this time. I would recommend its use only for companies who can’t afford a better antivirus, i.e., companies with ten or fewer PCs that can use the free version. For home users, AVG and Avast are superior and also free for home users.

  9. Tom

    I tried running two AVs at once. AV #1 would find a virus and move it to its quarantine area. Immediately AV#2 would detect the virus and move it to its quarantine area. The AV#1 would detect…….
    you get the idea.

  10. Zakariah

    Why are you still on Vista. I can tell for the title bars

  11. Fyrewerx

    While not as convenient as Malwarebytes (which I often use), I run my monthly scans (or more often depending on activity) on my PCs using AVG Rescue CD or AVG Rescue MemStick (with a lockable USB memory stick). Restart the PC with the Linux based CD or memory stick inserted, and proceed with a complete scan. After the AVG loads, and before scanning, there is an option to check for and load the latest virus data info. At the end of the scan, it generates a report, and provides choices of what to do with any issues found.

  12. Werner Maertens

    I Have Microsoft Security Essential, and Avast Internet Security Internet.
    Both programs are running together ! HOW to let them Run when I want them to run ?
    If someone got any Idea please let me know… My email adres is :
    Yes I live in Tenerife, so it’s a es at the end ,…
    Have the SNAP.DO search toolbar / search page comming Up ,…Out of the cloud, and don’t know what to do to get this Toolbar OUT of IE9 32 and 64 bit, and out of Firefox browsers.
    I have asked friends, but NOBODY seems to come with a Solution, for this problem !
    The internet got some Ideas of solutions , but Not one is Working.
    Warm Regards, and thanks in advance !
    Werner Maertens

  13. bedlamb

    2 MrCuddles
    You can use Autoruns from Sysinternals. Un-check entries from AVG. But, every time you run its scanner, you should check autoruns to be sure AVG hasn’t reinstalled startup entries. If it has, just un-check them. I’ve used Avast and liked it. I haven’t run AVG on my own machines, but un-installed it from 14 machines at work because of problems. As a secondary scanner, it should be fine. Remember to run update before scanning.

    2 gyffes
    ThreatFire was great on XP.

    2 Zakariah
    I too use Vista at home. I like it better than 7. I plan to continue using it until support ends in 2017, afterwhich I’m hoping to switch to 9 if I like it. If 8 is my only option, I’ll quit dual booting and just switch to Ubuntu full time.
    Vista isn’t the same system that came out in ’07. SP 2 is equally proficient with 7, and to my mind, better organized.

  14. Data Dope

    Anti Virus is only ONE THING! There’s still a matter of malware or even simple poor maintenance to think about (translation: user error or configuration error). There’s also a little matter of root kits or even actual physical damage such as a failing hard drive too. So just being able to detect a virus doesn’t really mean you’re safe or “bit-proof” (a word I like to use instead of “bullet proof”).

    That said, I really like the Microsoft Standalone System Scanner (MSSS). You just can beat booting to a completely different OS – from Microsoft no less – to do an in-depth scan. I like doing it about once or twice a month.

    Loading MSSS or any other similar tool on a thumb drive and then booting are really the only hard parts to it. There’s also Avira or even Kaspersky just to name a couple of other freebies. Just be sure the A/V engine and support are up to date so that even rook kits can’t hide. Of course, the downside might be that you don’t get to use your computer during the scanning (except for maybe Kaspersky which also has a stripped down web browser and a few other things).

  15. MikeMoss


    I run MSE for my primary always on antivirus software.
    But for years I’ve also run both Malwarebytes and SuperAntiSpyware as well.

    Neither one is in an always on configuration, but I update and run them both every day.
    It only takes a few minutes but it will find anything that MSE doesn’t.


  16. Andrew

    This seems like a lot of work! Would you recommend it to a simple user like me? I have only one antivirus installed (Unthreat Antivirus) and so far I’m happy with it and haven’t gotten a virus even though I download a lot of stuff from the internet. I’d love to hear your opinion.

  17. Jenita

    I use Comodo antivirus coupled with it’s firewall,it works fine, i am satisfied with that, i highly recommend this product.

  18. Carol

    I also have 3 programs that run daily: MSE, Malwarebytes paid, and SuperAntiSpyware paid. All 3 are scheduled to run at different times and are set to update daily so I don’t even have to do anything at all. I have 8 computers that I take care of (family members) and having these 3 programs on them has kept everyone safe for years, in spite of kids who go to risky sites. Free is wonderful, but Malwarebytes and SuperAntiSpyware are well worth the cost to purchase for the piece of mind I get.

  19. technocool

    Great Article. Keeping Malwarebytes along side one regular anti virus is really nice.
    But I really wonder why HitmanPro is not recommended, you can use it by installing.
    Or for a simple scanning one can use it without even installing, and it scans with 5 different online scanner, so like having 5 scanner at a time, and I think it’s really great, at least work for me.

  20. StevenTorrey

    I tried to connect to ESET and got nothing, nada, zip… So, wha’s up with that?

  21. J.B. Goode

    OK, I need some advice here (as do many who are probably afraid to admit it). I use one desktop computer, one notebook, a tablet and a smart phone. I am using Norton AV on the two computers and the smartphone, nothing on the tablet. I never heard of the AV programs mentioned in the article or comments. I saw no mention of Norton or the ubiquitous McAfee. I am not aware of ever being affected by virus or malware. What am I missing here? Thanks.

  22. Xander

    Pretty much the only site you’ll ever need for a quickscan of a single file.

    Use ESET Smart Security for main AV, or may be Kaspersky.

  23. Vic

    It is not true that 2 antiviruses cannot necessarily work together when their background scan is not off. I used to run McAfee 6 and McAfee 8 together for quite sometime, without any problem. It was interesting that their engines differed and even based on the latest updates, sometimes some of them reported a file that the other one ignored (but most of the time they both detected the virus)… Anyways, it is possible…

    After seeing that BitDefender is one great antivirus that had the best rate of detections at that time (5 or 6 years ago), I always use it as my backup antivirus. I use it when I download something and my main antivirus does not find anything. My main antivirus is Avira. It is both light and with a very good rate of detection.

    Besides, I also use MalwareBytes AntiMalware occasionally.

    And if I have a malicious file that no antivirus detects it, I send it to VirusTotal and counsel it.

    It is some few years (for example 5 or 6 years maybe) that my system has not become infected at all.


    One good point that is missing in every tech site is that VirusTotal does not only scan file or URLs. It also immediately sends the files to the labs of all those antiviruses for either more investigation (if they had not find any suspicious file) or for analyzing the prevalence of threats. I asked this directly from its creator and he responded the above to me. Because, I used to send suspicious file samples to McAfee labs for further evaluation and possibly including in their new DAT files, and I suggested the same thing to the creator of VirusTotal, and the good news was that they already do so, whenever an antivirus does not consider a file suspicious.

    So sharing your suspicious files with VirusTotals means sharing your files with all AntiVirus Labs simultaneously (as far as they do not already detect it – if they do detect it as virus, VirusTotal does not send the file to them, and only sends the statistics)…

    So I urge everybody to scan any file they suspect using VirusTotal and let the databases of all the available VirusCheckers get updated by receiving the new suspicious files.

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