I don't use any antivirus software myself because these days I use Linux, and even back when I used Windows I managed to get by without any antivirus software (not to be attempted by lusers, noobs and mortals) due to being computer literate and security conscious.

However, I would like to know about antivirus software for when computer illiterate friends and relatives ask.

It is difficult to pick antivirus software because there are many variables to take into account, such as detection rate, false positive rate, resource usage, price, etc.

Commercial antivirus software are made to appeal to the broad masses of end-users, and on a subscription-bases business model the end-users needs to be reminded and hence the software is often very obtrusive and invasive, plastering itself all over the system; start menu, desktop, quicklaunch, quicksearch, toolbars, control panel, browser, extensions, everywhere.

People like to know they're getting something for what they're paying, if the software stays out of the way and they don't notice it - they don't want to pay for it. Many antivirus companies are making an income based on fearmongering and seem about as shady as the people/companies writing malware.

Antivirus software are often huge, bloated, slow, invasive, obtrusive resource hogs and sometimes ironically are more difficult to uninstall (get rid of) than viruses. With antivirus softare the cure is often worse than the disease.

Many of the software suffer from the kitchen sink approach, where there are "security suits" that force upon me anti-malware, anti-spyware, anti-rootkit, anti-keylogger, spamfilter, sandbox, intrustion-detection system, firewall, etc. Tons of stuff besides the antivirus that I never wanted or would like to get from another provider.

The question seems not to be 'which antivirus software is the best?' but rather 'which antivirus software sucks the least?'.

Microsoft Security Essentials and Avast seem to be the top two for sure.

Product of the year according to AV-Comparatives.

2010: F-Secure

2009: Symantec

2008: AVIRA

2007: ESET

2006: ESET

2005: Kaspersky

2004: Kaspersky

Wow, Symantec was actually on that list... -scary-

I voted for Avast. Avira very good, but it nags you to "upgrade" to the paid version. If you're paying, that's not a problem.

In the most recent AV-comparatives tests G-data did the best, both the on-demand test of detecting known malware and the retrospective/pro-active test of detecting unknown malware. Low rate of false positives, too. Avira was not far behind.

... 'which antivirus software sucks the least?'.

sucks the least says it all!!

I voted for MSE (Microsoft Security Essentials) because, in practice, it works. It is also pretty lightweight, runs OK on older hardware and doesn't force you into loading about a half-gigabyte of extra rubbish into memory.

I just disinfected a customer's machine which was running both Avast and Spybot.....

Most AV's are capable of completely trashing Windows when the detection updates go bananas.

McAfee and Trend are pretty good at trashing entire networks and domains, so, for me, they suck the most, along wth Clam AV which has appallingly bad detection rates.

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McAfee and Trend are pretty good at trashing entire networks and domains

I think all security software is capable of screwing something up in a big way.

Maybe 2 years ago I updated Avast (program, not database) and it apparently ignored my settings of "warn me, don't delete anything". I scanned my system and maybe 2 or 3 days later I was perusing my freeware partition and hundreds of sfx archives were missing. I saw the .md5 and was wondering "what did I do with the archive", started looking and noticed folder after folder, work I had accumulated, copied websites, how-to's I created and put into pdf form, and programs - all were gone.

Avast just had a database update issue around 4-12, if I remember correctly system files were being deleted. I have to own my bone-headed mistake of not paying attention to my scans, I should have double checked settings after the update, before I ran a system wide scan. The database issue - Avast owns that IMO.

I'm sure it is a headache coding security software so I try not to be too harsh, when they are on all is good, make a mistake and off with their heads.

AVG has also hosed Windows several times in the past.

Well, in line with what gUiTaR_mIkE said, they have all screwed up at some time in the past.

To my certain knowledge AVG, Kaspersky, McAfee, Symantec, Trend (in alphabetic order) have all hosed Windows at some time.

Symantec is quite a bit better than a few years ago and I would recommend SEP (Symantec Endpoint Protection) for networks except that the Management Console managed to trash my WSUS server several months ago. Took me until about 4am (working all night) to get it working again.

Ironically, the Trend product causing the most grief is called "Worry-Free" :cry:

Any of them should be set to ask before deleting anything, for sure, and deleted files should be sent to quarantine instead of just trashed.

You should make regular disk images to fully back up your system, in any case. AVs aren't the only thing that can hose your OS.