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Several anti-malware programs can cause conflicts if they are all trying to run real-time scans together.

I just had a computer crash. The so-called blue screen of death. My technician found it was a simple problem: software conflicts. When asked to explain, he said, "You have Kaspersky. You don't need all of those other things." He took the following off my computer: Spybot, Malwarebytes, McAfee, etc. I believe you had said that the Malware program was compatible. Did I misunderstand? I use Windows XP and I was installing a wireless adapter.

In this excerpt from Answercast #83, I look at the dreaded blue screen of death caused by conflicting anti-malware programs.

Several anti-malware programs

Well, you misunderstood, probably.

You know...'s tool is in fact compatible with most things. If I had to pick a specific compatibility issue from what you've listed, it would probably be Kaspersky and McAfee together.

Conflicting virus and spyware tools

Here's the issue. Most of these anti-malware tools install something that's called "real-time scanning."

That means that while you're using your computer, the software is actively looking at what you're doing (the files you're manipulating - the things that are coming and going on the internet) and checking them to make sure that there's no malware in those files.

Having one program do that is perfect. Having two programs trying to do that at exactly the same time?

Real-time scanning

That's what we talk about with real-time scanning; they're trying to do it as you're using the computer. If more than one program is trying to do all this monitoring while you're using your computer, they can conflict.

In the worst case, it can conflict in the way that you've just described. You can in fact get a blue screen, particularly under Windows XP.

Limit real-time scans

The real way to use most of these programs is to have one good base software installed.

Kaspersky? That's a fine one. I happen to recommend Microsoft Security Essentials - that's another one. Have it installed and have it configured to do all of the real-time scanning you need.

Other programs can still be installed (Malwarebytes being one of them) as long as you don't have their real-time scanning enabled. In other words, they sit there, but they're not running.

Scheduled scans and problem shooting

Now, why would you have them installed if you're not running them?

Well, two reasons: one, you can have them run a scheduled scan - a scheduled scan is not the same as a real-time scan.

A real-time scan is happening all the time, monitoring what you're doing. A scheduled scan does nothing more than periodically take a look at the files on your disk.

  1. That isn't likely to conflict with the real-time scanner and;

  2. It happens in isolation. It happens at that specific time, not all the time.

Malwarebytes will do that. Most of the other utilities will do that.

Diagnosing problems

The other reason to have a software package like Malwarebytes installed, but not necessarily monitoring in real-time is because you might need it.

In other words, Malwarebytes is one of those tools that we often recommend and say, "You know what? I've got malware. My regular program didn't clean it up, isn't catching it. What can I do?"

Malwarebytes is really good at catching some of the things that some of the other utilities don't.

So, that's what it boils down to... having too many anti-malware programs all trying to scan in real-time as you're working with your computer is a situation that will lead to conflicts. Those kinds of conflicts can result in the dreaded blue screen of death.

(Transcript lightly edited for readability.)

Article C6196 - December 30, 2012 « »

Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

January 1, 2013 8:39 AM

Just a comment to let you know I am successfully running "Vipre AV", "Malwarebytes Pro" and "SUPERAntiSpyware PRO" on my Windows 7 Home Premium computer, all with active scanning or protection enabled with no problems. I agree with Leo in saying that the main issue is not to run two "AV" programs together. There are warnings all over the internet about this issue.

Best Regards Everyone

Mark J
January 1, 2013 9:03 AM

SuperAntiSpyware and MalwareBytes are not antivirus programs, but fall into the category of antispyware programs. For some reason antispyware programs running active in the background don't seem to conflict with an AV programs as much as running two active AV programs at the same time. I still wouldn't recommend it, simply because I prefer to run as little in the background as absolutely necessary, as a lot of stuff running in the background uses up precious RAM.

January 1, 2013 9:11 AM

I am surprised at the misunderstanding by the poster. As he is experiencing (or was) conflict - surely he realised, as he was using 'paid-for' versions that this aspect is what he is paying for?
That is to say 'Real-Time' protection. By the way, one of my great favourites, which is FREE, is Threatfire which, as near as dammit is (and probably is with my limited knowledge) running in real-time - try putting a foot wrong with this installed and you will be very impressed.

January 1, 2013 9:32 AM

That was very clear and explains a lot of computer slow downs and stops. Thanks! I find AVG the best freeware. Malwarebytes is like the vacuum cleaner, keep it in the cupboard till you really need it same goes for Microsoft Security Essentials that one will really slow down your YouTube play back.

January 7, 2013 4:43 PM

How can I tell if a program is "realtime" scanning? I have Zone Alarm & Malwarebytes, should I uninstall Spybot?

Thanks for your web site Leo it's a great help.

Mark J
January 8, 2013 12:32 AM

You can tell if an antimalware program is scanning in real time by going into the options for that program and seeing if the real time scan is on or off. I would only run one AV program and possibly one antispyware program at a time. If you are running the Zone Alarm suite with antispyware in real time, it's generally not necessary to run any other antispyware program in real time.

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