Antivirus programs are rubbish
All of them.
Not using one, especially on a computer used by teenagers, would be tantamount to professional suicide for the person who has to maintain said computer. However, I have yet to find an antivirus product that doesn’t, at some point, create serious problems of its own on a domain network.
Two years ago we stopped using Symantec Antivirus Corporate on our network after it started corrupting network profiles for almost every user in the school. Worse, it did so in a very subtle way which took weeks to track down. We gave Symantec the boot about a month later. Symantec are also the company behind Norton Antivirus, which about 10 years ago was the best product going; these days I can’t discourage its use strongly enough. I see more broken Norton installs than every other AV product combined, and its uninstaller is so fragile that I cannot remember the last time it actually worked.
Sophos is popular in school networks in the UK, because it’s very cheap. It’s also very ineffective in my experience.
The last time I used McAfee Antivirus was at university. They had a full academic licence that permitted students to install it on their own computers. I uninstalled it in disgust after a lot of my files were automatically deleted in a ridiculous false positive incident a few years ago that saw me trying to explain the very concept of a false positive to McAfee support, who insisted that no such thing could exist. The problem was made worse by the fact that I had configured McAfee Antirivus to always ask before deleting any file it thought was infected, and it ignored that setting completely.
At the time, I started using AVG Free, and so when we dumped Symantec at work, we switched to AVG Network Edition. Now, before I go on, let me say that I still recommend AVG Free for home use, and the small business I look after that uses AVG Small Business Edition has no issues. However, AVG Network Edition has seriously let me down on three occasions in the last few months, and I have decided it may have to go. The sad thing is that version 7 had no problems at all, while version 8 has given me nothing but trouble.
The question is, what next? Ask an IT professional for an alternative and you will get a dozen answers, followed by a dozen replies by different people recounting tales of decrepitude when using each suggestion you’ve just been given.
I get that creating an effective antivirus product is complicated. If it was easy, everyone would be doing it. I just wish that someone could not only get it right, but then manage not to destroy their own product six months later.