Can I run two AV systems?

That's a good question Robert. I'm sure we've covered it before, but things change over time so it's worth revisiting.

There's no absolute rule because different AV products work in different ways and do different things in your system. If I have to give one simple answer it would be:

Use one reputable product such as AVG and trust it.

And as a rider to that:

If it makes you feel safer, use another one-time system scanner occasionally.

One of the reasons that you wouldn't want to install two AV systems at the same time is that they could interfere with each other, or at the very least get in the way of the smooth operation of processes such as email.

It used to be the case that some AV programs worked by containing signatures of known viruses, and these signatures could be detected by the other AV program as a virus,. I don't think that's a problem nowadays, but it could be.

When you install a new AV program it will often warn you that there's another one installed and require that it be uninstalled. Yes, this might just be sour grapes, but if you're going to trust the new package, you should probably follow the "rules".

We asked AVG Australia to comment, and this is what the Marketing Manager Lloyd Borrett said:

Generally, it is not a good idea to run multiple security applications of the same type at the same time, especially anti-virus, firewall and security suite programs. To be truly effective, security applications have to run in the background in real time. Thus each one will have some impact, albeit minor, on your system resources and performance. However, many security applications that perform the same functions don’t play well together. They often conflict with each other in ways that can slow your computer to a crawl, or even crash your operating system. This is why AVG recommends uninstalling other anti-virus applications before installing AVG Anti-Virus Free Edition 8.0.

Some anti-spyware applications run in an “on-demand” mode, only scanning your computer whenever you request it, instead of in real-time. Thus while you could have more than one of these applications installed, it’s unlikely that you would be any more secure. All reputable security applications, like those provided by AVG, do a good job at protecting you from threats provided they are kept up-to-date. The important thing is to keep your security applications, plus your operating system and commonly targeted utilities (e.g. Adobe Reader, Apple QuickTime, Adobe Flash Player etc.) fully up-to-date. Using system resources to check for and install updates is far more beneficial than running multiple security applications.

So, what experiences do other readers have to share?

Paul Zucker

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