Helping people with computers... one answer at a time.

I tend to avoid simultaneous virus scans. What's more important is to make sure your several tools are not competing as they search for various types of malware.

Hi, Leo. This is a more general question. I'm trying to ensure that I don't create a problem on my computer. I'm using Windows 7 Home Premium and I have scanning software programs including AVG 2011 Scanner - Malwarebytes - Spybot - Windows Malicious Software Removal Tool and Paretologic P.C. Health Advisor. Rather than waiting to use these one at a time, is it OK to run four or five of these scans at the same time?

I definitely do find that some of these find items that the other scans did not, so running just a couple of scanners does not seem to suffice. What is found seems to be tracking cookies, not anything particularly dangerous but in the case of a virus, I do want to carry out these scans fairly regularly. If I can run all of these scanners at the same time, it would be very helpful.

Also should I clean or delete any items found at the end of the scan or not until all of the scans are complete? I wonder if I would compromise anything if I deleted something that was being scanned by another scanning process. Sorry about the lack of correct computer terminology, Leo. I'm a novice in computing. Thanks very much for your help.

In this excerpt from Answercast #20, I look at the issue of running several scanning programs for different problems, such as virus, spyware, and malicious software, at the same time. What is overkill?

Multiple malware programs

I tend to avoid simultaneously scans if at all possible.

Now, one of the things that you've noted here is that some programs are finding things that other programs are not. Given the list of programs that you have installed, that's totally expected because they are not checking for the same thing.

  • You do not have five anti-virus scanners for example. You have one.

  • You do not have five anti-spyware scanners. You have one.

Malwarebytes kind of straddles the two, but fundamentally, it's really both and neither. The Malicious Software Removal tool is not really the same kind of a thing as your anti-virus and anti-spyware tools.

In reality, each of the five different things that you've got running there are mostly scanning for and looking for different things. I would absolutely expect to find different results.

Tracking cookies

I would absolutely expect tracking cookies to be one of the biggest areas of additional reports by some tools as compared to others... because there's no agreement on just whether or not tracking cookies are a serious threat or totally benign. I tend to think of them as totally benign, but I know that there are spyware tools that will report them.

Multiple scans

Now, when I say that you've got five tools running five different scans, there is definitely overlap. Malwarebytes will certainly find some things that nobody else does, but Spybot, for example, will probably find a few things that Malwarebytes does so I'm not terribly concerned about the fact that you've got five different things. It does feel like overkill.

I would definitely not run five scans simultaneously.

I think you are asking for trouble in those cases where the tools might overlap.

When to delete

When something reports a problem, whether or not to clean or delete it really depends on the specific problem:

  • If it's a virus that's being reported then absolutely, clean or delete it.
  • If it's malicious software that's being reported, absolutely clean or delete it.

But if it's cookies, if it's tracking cookies, like I said, I don't see them being such a huge problem. I know many people get quite paranoid about their activities being tracked on the internet. I just don't think that I'm that interesting to the world and I really don't care if there are tracking cookies on my machine.

That's a case where you need to make a decision for yourself. Since, by definition, we're not going to run multiple scans simultaneously, then the whole issue of deleting something while it's being scanned doesn't pop up as an issue.

What tools to use

In your case, I definitely understand wanting to stay safe.

I would probably remove the Paretologic Tool and maybe the Malicious Software tool from your scanning. In fact, I would probably also remove the automated scans by Malwarebytes.

My approach typically is to have a good anti-virus tool (AVG qualifies), a good anti-spyware (Spybot qualifies), and then have additional tools that I might use for further diagnosis only if I, for some reason, feel the need.

If there's a need

Malwarebytes is what I reach for first, in a case like that. The Malicious Software Removal tool, I believe, will run once a month on its own anyway. You don't have to do anything about that.

To be honest, I'm not totally sure of exactly how deep Paretologic Tool scans or exactly what it scans. It's not something I've ever felt the need to recommend: that people go out, get, and add whatever it does to the mix.

Virus and Spyware scans

So I do think you're probably scanning a little bit too much. I would not scan all five things at the same time.

And, I think your terminology is fine. It definitely got the point across!

Next from Answercast 20 - Can my ISP know if I am using a VPN?

Article C5380 - May 24, 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?

May 24, 2012 5:21 PM

"Hello Leo",

I am Chris - the person who submitted this question[s] - Thank You very much for your reply to Me I really appreciate it.

I will definitely Stop carrying out the simultaneous Scans - Thanks for the advice.

The Paretologic PC Health Advisor Scans for Virus`s - File Problems [and can apply Fixes] - Driver Problems and directs You to where Drivers can be Downloaded from - websites that have been `Checked` and are recommended by Paretologic - Guaranteed Virus Free Downloads.

Plus there are `Tools` that enable Optimise and Manage items on the Computer and can help You to correct some types Problems with your Computer - this Software has definitely helped Me to solve what I thought were Difficult Problems in the past.

I personally would definitely recommend Paretologic PC Health Advisor - although this is because I am a complete Novice in Computing and it has enabled Me to `Fix` Problems that have occured - I could not be classed as a `Technical Reviewer` of this Software.

It is a `Commercial` Software [Paid For Subscription] - Yearly Subscription - which I have been using for 2 Years and I renewed My Subscription only 2 Days ago so I would not want to discard it / not use it.

Thank You very much once again Leo - I really appreciate your advice.



May 26, 2012 4:20 AM

I've ran more than one malware scanner at the same time and they froze my machine.
Now I run them one at a time, usually after I'm done for the day and relaxing with a book and don't have to pay particular attention.

May 26, 2012 8:51 AM

"Hello", I have wondered about this for as long as I have been using a Computer which is only about 3 Years.

I had initially not carried out Scanning with multiple Scanning Software Programs - out of `Fear` and lack of ANY knowledge on Computing BUT I was then told by various Friends who I asked about this that it would be `O.K.` !

For about 2 Years I HAVE been using Multiple Scans simultaneously - although I obviously cannot be sure that this has caused any problems [?].

I have had Windows Explorer Problems and on one occasion I had to carry out a Restore to a previous `Known Good Configuration` to solve a problem that I just did not have the Computer Knowledge to Fix.

I will now be doing exactly what snert mentioned - Carrying out the Scans ONE at a time while doing something else or just relaxing near the Computer.


June 24, 2012 4:53 PM

is it ok to have more than one malware and spyware programs installed on a pc.i have malawarebytes and spybot S&D together with kaspersky antivirus software installed on my pc will there be any conflict with them.and also have comodo firewall

June 24, 2012 9:01 PM

You will have a problem if they try to run their scans at the same time as they might bump into each other.

Comments on this entry are closed.

If you have a question, start by using the search box up at the top of the page - there's a very good chance that your question has already been answered on Ask Leo!.

If you don't find your answer, head out to to ask your question.