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Do I Need More than One Anti-malware Tool?

With regards to firewalls, anti-virus programs and anti-spyware programs: can I have more than one of each of these programs installed in my computer? For example, I run ZoneAlarm; does that mean I should I turn off Windows firewall?

The answer to this question used to be a very complex “yes”. It used to be that getting all the protection you need involved running multiple programs. And, as you might expect, running multiple programs, if done incorrectly, can result in problems.

Today, things are simpler.

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What you used to need

Once upon a time, you needed three separate types of security tools:

  • Anti-virus: these tools scan for known patterns of data found within previously identified malicious software, or watching for those patterns in data being downloaded to your computer.
  • Anti-spyware: these tools monitor for suspicious behaviors or changes on your system associated with software attempting to spy on you.
  • Firewall: these tools block access to your computer over your network connection.

It was complex, because some tools in one category attempted to cover (or partially cover) one or both of the others — often poorly — and could easily conflict with other security tools installed.

No longer needed: a firewall

I want to remove firewalls from the discussion right away. It’s not that you don’t need one — you do — it’s that you likely have one (perhaps two) without even realizing it.

  • Your router acts as a firewall. For many years, I’ve suggested that’s all you really need.
  • Windows now includes its own software firewall, and since Windows 7, it’s enabled by default. This, too, would be enough by itself.

The two together handle any firewall needs quite well. I see no need to install an additional firewall.

Today’s standard: a single anti-malware tool

“Malware” — short for “malicious software” — is an all-encompassing term for viruses, spyware, and anything else we might consider harmful.

Anti-malware tools today cover both anti-virus and anti-spyware.

In many ways, this was inevitable, as the line between the two has become blurry. More and more viruses employ spyware-like tactics, and a lot of spyware acts more like a virus.

That the tools to scan for either would merge into a single effort only makes sense. And that’s what the industry has effectively settled on.

I used to say that a single “security suite”, as they were once called, typically compromised the quality of either the anti-virus or anti-spyware component. For example, they might be a good anti-virus tool being packaged with a lower-quality anti-spyware tool.

Today, that inequality has mostly fallen by the wayside, and you’d be hard pressed to find a tool that doesn’t address both adequately.

Windows 10: you have all you need

If you’re running Windows 10, you already have everything you need.

  • The Windows firewall is enabled by default.
  • Windows Defender is enabled by default, and handles all anti-malware needs.

You’re welcome to install an additional anti-malware tool if you feel the need. If you do, Window Defender will turn itself off and stay out of the way, so you’ll still only be running a single anti-malware tool.

Multiple anti-malware tools can cause problems, which is why Defender steps aside. The same is true if you install even more security software. The potential for conflicts between the software increases, which, in the worst case, can prevent any of them from working properly.

You need only one, and for most people, that one is Windows Defender.

A case for more than one

There is one scenario in which an additional anti-malware tool might be called for.

If, for some reason, you suspect malware has made it past the anti-malware tool you run normally, it’s advisable to download and run a different tool, from a different vendor, and run an additional scan.

If your primary anti-malware tool is Windows Defender, remember that it steps aside if another anti-malware tool is installed. That means you’ll either need to switch to the new tool you’ve just downloaded and installed, or you’ll need to uninstall it once you’re done, making sure to confirm that Windows Defender is enabled once again (just check its settings).

Note that when installing an additional tool alongside another that doesn’t step aside, it’s important to avoid enabling any “real time” scanning, as that’s where multiple anti-malware tools most commonly conflict.

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42 comments on “Do I Need More than One Anti-malware Tool?”

  1. This set me thinking ! I have been unable to install NAV for the last week, it keeps failing and asks me to start again, and keeps failing to install.
    I notice now that Windows Firewall is ” ON “, thats got me thinking — thats good !! I will now have to learn how to uninstall Windows Firewall, etc. Thanks for the education.

  2. I agree on the Firewall you can only run one firewall at at time. I use ZoneAlarm and it automatically turns off the XP firewall. As for AntiSpyware I have Windows Defender and SpywareDoctor running, and the PC does run a little slower, but the protection works. And for AntiVirus, on my new dual-core pc I have both AVG & Avast running with no problems. I chose AVG for the scheduler, and Avast for the boot-scan.

  3. Well, I use F-Secure Internet Security full time now (anti-virus, anti-spyware, and firewall) all in one package, but when I installed it, I forgot to uninstall Avast A/V and ran into all kinds of problems, (freezes, crashes), but that all stopped when I got rid of (uninstalled) the Avast. F-Secure disabled my Windows Defender & Windows Firewall by default upon installation and so far, so good.

  4. I have an avast anti-virus (Avast) and windows defender/firewall in my laptop. I was planning to add either Symantec’s Conficker (aka Downadup) tool, Trend Micro’s Cleanup Engine, or Malwarebytes due to this conficker virus. should i go for it or would any of these conflict with my current protection or are my current system enough?

  5. Hi Leo,

    When choosing a firewall what are main criteria it should match ??

    How about NODE 32 SMART security, what’s your opinion about it ??

    Thank you.

  6. If this author thinks that “as a general rule, you only need one of each”, then he obviously doesn’t have any experience with cleaning malware off of computers.

    Armchair technicians for the lose.

    Realtime protection is one thing — obviously you only want one RT AV running at a time. But no single AV, AS, AA, or other AM program is ‘all you need’. Any tech who has any amount of experience cleaning malware can tell you that no single program will get everything.

  7. Remember the key is you should not install nore than one real-time background scanning security program. Most people will do fine with just a simple hardware firewall (router), Windows Firewall, Windows Defender (Vista/7, Keeping Windows updated,having a real time basic virus scanner like Norton or McAfee and then using an on demand product like Malwarebytes for when you think there may be a problem.
    Read about Windows 7 upgrades on my blog

  8. I run 2 different anti-virus programs at the same time. I have run avg and Threatfire, and am now running Avira and threatfire. I left avg because it has become a resource hog. I have not had any problems doing this. Threatfire was designed to run with other anti-virus programs and works different than other programs and can catch viruses that have not been fixed yet. As I have only used it with these 2 programs I can not vouch for it running with any other virus programs. Check it out at you may change your mind about running 2 virus programs at the same time. I used this type of anti-virus program for many years as my only virus program. since the Dos days and have only had 1 virus in the whole time.

  9. Mortal enemies??? Example: If you install Kaspersky and Spybot Search & Destroy, Kaspersky gets “mad” about Spybot. When you go to uninstall Spybot, their uninstall program asks you “why?” One of the listed options is: “Kaspersky.”

    Next, Spybot comes back with a paragraph explaining that they have thoroughly tested their product in conjunction with Kaspersky, and can NOT find any conflicts.

    On the flip side of that coin, if you have Lavasoft’s Adaware installed, and try to install Spybot, Spybot warns you that the two products are incompatible!!!

    So who is speaking with a forked tongue?

    Also, the rules of the game change on a daily basis. So two programs that were completely compatible yesterday may not be today because one of them was updated.

    Hence, Leo’s concept of not running more than one of each type of program is generally the safest bet. Exception: My computer was acted very strangely for quite a few days. Kaspersky didn’t find anything wrong. So I “cheated” and installed Spybot, ran it, if found one problem, disposed of it, and now my computer’s performance has greatly increased. Of course, I immediately uninstalled Spybot after running it to avoid any potential conflicts with Kaspersky.

    Those are my thoughts…

    Aloha from Hawaii,

  10. I have but one question: I have Vipre antivirus and it seems to be doing a very good job of scanning my system. Why is there never any mention of Vipre anywhere (at least where I have looked)?

  11. Hello, I found out that free antivirus, spyware firewall and so on don`t come complete, how may I assemble a package made up of free software: for example: avast free + zone-alarm firewall , and some other free peer to peer free protection and so on to be able to get it all as good as it gets without paying for commercial products (or downloading them illegally) ? Thank You! take care! Daniel

  12. The new Panda Cloud Antivirus appears to run fine with VIPRE Antivirus/Antispyware/Firewall with no apparent conflicts or system slowdown. Also it is good to run an on demand manual scan for viruses once in a while with various products.

  13. I am running norton 360 and Avast antivirus both at same time recently have been having a problem with down load speed suppose to have 8mps and only have 116kps could running them both cause this problem

  14. using more than anti-virus program is possible.But your computer may run, slowly or stop, in some given time. is it my advise and opinion, to run on a reliable one anti virus.

  15. I am running AVG 2011 also have IObit 360 on here are they ok 2 run @ same time also microsoft security essentials is on here but its off as it wouldnt allow me 2 turn on defender i recently removed trojan and think it has done severe damage as my security centre wont always stay on i have 2 use Advanced system care 2 turn it bak on anny advice would be much apreciated as i am not only fixin my comp but i fix m8s comps a bit 2

  16. I’m using superantispyware and spybot. I’m thinking of adding in Windows defender and all together Avast would be there with the rest as my body guards.
    Should I add in Windows defender? Is it worth it really?

  17. Microsoft Security Essentials installation instructions include the statement: ” You can keep your antispyware programs running, as they coexist peacefully.” Comment? True? False?

    I would believe what the program is telling – why would it lie? It will also warn you to remove other anti-virus programs.

  18. For over 12 months, I’ve been running MSE along-side Avast, and using Search & Destroy for it’s immunization and the odd scan.
    When I had issues with Avast (v7 does not seem to run on my machine at all) and had to get rid of it, I soon managed to get a virus.
    I’ve now managed to re-install Avast v6, I have had no problems sinse.
    As a side-note, I have been thinking about adding Zone-Alarm’s firewall to the mix, as I’ve used it in the past. Is it worth the extra effort to replace Window’s firewall?

    In my opinion, no.

  19. If I use the one Mfg’s anti-virus software (tested as the best percentage in CATCHING viruses), can I use another Mfg’s software (tested as the best percentage software in disabling/removing it)? And if so, must I somehow get the caught viruses out of the catching program’s quarantine area or vault?

  20. I am running Avast! (paid edition) and Microsoft protections (anti-virus, anti-spyware, firewall, ) simultaneously. The Microsoft protections are built into my IE 10 and Windows 7. Should I continue using Avast! or remove it from my system?

  21. I have been using (at home) Norton 360 Multi — which is supposed to be Anti-virus / Firewall / and (I think) anti-malware (not so sure about that).
    I also run Malwarebytes Anti Malware pretty often… There do not appear to be conflicts (at least I have not seen any) though when I first did this, the Norton product “objected” to the Malwarebytes product — I assume that the two have “hugged and made up”….
    I also have a router… (and, on the wireless side, use the WPA2-PSK (with AES) to encrypt the connection, as well as
    use MAC Address filtering) My thinking is that this combination should be adequate…..

  22. Very good info. but how do I know if my software combo is good. For example, I am running Symantec Endpoint Protection (from work to use at home) and malware by “Malwarebytes”. Is that redundant or just overlapping?

  23. I have AVG Antivirus free and Advanced SystemCare pro. From all you guys have said should i remove one and leave and + Ccleaner? Thanks

  24. For Leo:

    On your site I see “Spyhunter” recommended plus “Mindspark” being recommended as well…
    Elsewhere I see this MINDSPARK being touted as ONE OF THE worst MALWARE predators!!!!!!!!!
    Which I right?
    Are all of us non-techies being taken for a big ride?
    I use NORTON anti-virus 360 and even they tell us that I dont need others such as MALWAREBYTES or SPYHUNTER because Norton does it all and does not need conflicts!!!!!!!
    Where do I go from here????

    Tks Leo,

    • Spyhunter and Mindspark aren’t recommended by Leo. Those are just ads which happen to appear on the site. It seems that you might have mistaken an advertisement for some kind of recommendation. Ask Leo! actually has only limited control over the advertisements that are displayed. It’s important to realize that for any website, not just Ask Leo!, an advertisement should never be interpreted as any kind of endorsement.
      You can find more details here:

      • I am considering the option of having the free version Avast installed on my Windows 7 Home Premium computer?. I currently run Norton 360 Premier Edition and Windows Defender on that computer, plus Windows Firewall (I have the Windows Firewall disabled because Norton has a built-in firewall). If I am going to have the free version of Avast installed to periodically run scans on my Windows 7 computer, what all should I disable before installing Avast? I know that you (Leo) said that it’s okay to have two antivirus programs installed on your computer as long as you don’t have both real=time monitoring functions enabled at the same time, but I don’t particularly agree with that, and I would like more info.

        • The problem with running 2 AVs in realtime scanning modeis that they can conflict with each other and cause a myriad of problems. If you are running Avast, it would be best to disable real-time scanning on all other AVs you have installed. Then you can periodically run as many on demand scanners as you like. I have Avast, and I have my computer scheduled to run MalwareBytes to scan my computer and Macrium Reflect to backup every night wile I’m asleep. Some say that the nightly scan is overkill, but since I’m already paying the electricity to run my machine 24/7 I may as well take advantage of the time to have an extra small layer of protection. I’d also reenable the Windows Firewall as the free version of Avast doesn’t include a firewall.

  25. I was told by Avast help, when I called, that I should shut down my Microsoft defender/firewall so that Avast may do its job properly that is why I came to this page to ask the question if I should do it or not.

    • Avast’s advice is the same as this article concerning Defender. Either disable live scanning or uninstall it. If your version of Avast contains a firewall, I’d disable the Windows Firewall otherwise, I’d leave the Windows Firewall running.

  26. I “downloaded” 2 different spyware removal programs to remove knctr, (tried the second because I can’t find the first) and haven’t been able to run a scan for either. How can I tell if either has been downloaded? Tried to use Windows defender but it wouldn’t run (said I had other programs running). Could the malware be preventing these from being downloaded and how can I get either to run a scan?

  27. I am running windows 10. Of course Windows Defender and Windows Firewall are installed. I also have RegCurePro and SuperAntiVirus and HitmanPro all installed on my computer. If I understand your comments, I should have only one Real time protection turned on.. Both have been turned on, and I have not noticed any problems, but was wondering if they are undoing each others work? If I only use one, which one is best to keep?

  28. Use Linux Mint instead of Windows.
    Has a firewall but you do not need Virus or Malware software.
    Burn a live DVD, boot from it and have a look. It’s all free.
    See their website, tells you all about it.
    This is written on a PC with Linux Mint 19 installed on it.

  29. i`m sticking with win 7 ult even after MS stops supporting it.
    i use MBAM security and they have advised me they can keep
    me safe after Jan. 2020. without MSE. maybe after MS stops
    supporting win 7 i can finally get rid of MSE. it never EVER
    catches anything. and scans that take an hour and a half are no fun.
    granted. it could be just removing it and not
    telling me. but if i can`t see what they did, i assume they didn`t
    do anything. can somebody tell me, does win 10 defender tell
    you what they did, or do they just do it?

  30. Firstly, Excellent site/posts. I run Windows 10 with no additional firewall or antivirus; left to windows inbuilt firewall and defender. However, for many, many years I’ve been running certain other programs just to “clean-up” PC particularly after major and minor updates. These programs I’ve also installed on family and friends machines that I look after. Getting them to run them regularly is one thing but for those that do I don’t get calls for major help scenarious; just the ‘how do I do this; I forgot’

    Programs I installed are:-

    1. Windows Washer – original version, never updated. No longer available in this edition. I swear by it.
    2. Winoptimizer v10. Yes there are many updates to this program but this version has ‘simple’ interface which family & friends aren’t confused by.

    Both complimentary to one another. These are the main ones but two others are:-

    3. Malwarebytes
    4. Ccleaner

    Both are free editions and I have provided update and running instructions to ensure they retain/continue using free versions and don’t install ‘adverised’ items

    Everybody seems happy and running without any major issues and support calls are few and far between.


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