Why is it not recommended to have 2 antivirus programs running at the same time?
In: Technology
One anti-virus, which is the one built in to windows, is all you need. Anything more is excessive and will slow down the system while hounding you with advertising, all while doing a worse job than the free windows defender that comes with your operating system
Antivirus 1 checks something.
Antivirus 2 sees Antivirus 1 is doing something and checks it.
Antivirus 1 sees Antivirus 2 is doing something and checks it.
Repeat.
Both Antivirus 1 and 2 are involving some serious security critical things, so they both read it as something that really needs to be checked.
The same reason you don’t have 2 chauffeurs. They fight over the wheel and eventually your car is gonna hit something.
Because each antivirus program “hooks” into computer operations that involve things like reading a file, receiving stuff from the Internet, etc. so that it can intercept the data and check it before it gets passed on for further processing.
This has a noticeable impact on system performance. And of course if you’ve now got two antivirus programs doing this, things slow down even more (plus there’s a risk that they won’t play nicely with eachother, which would cause worse problems than just slowness).
I guess if you could know for sure that one antivirus program only caught half of the viruses and the other one caught the other half, it might make sense, but in reality, *most* antivirus programs detect *most* of the same viruses, so there is no reason to use more than one considering the impact on performance.
And in fact with recent versions of Windows you don’t even need any antivirus program at all, because the function is built in and works well already.
Even having 1 antivirus program running is a bad idea and will slow your computer down, 2 it’s that much worse. Just run a decently secure operating system and don’t install random shit from dodgy websites and you’ll be fine.
Just want to make sure for anyone else reading through this as a follow up question, I can uninstall McAfee and not experience anything different on my pc other than a freedom of McAfee popups right
antivirus 1 sees antivirus 2 antivirus 2 sees that antivirus 1 checks it antivirus two attacks antivirus 1 attacks they attack over and over and over and over like two people with the same streght attacking forever it is just a waste of time and resources
Specifically, the advice is not to have more than one anti-virus tool actively protecting your computer.
The reason for that is because active-scanning AVs detect when the operating system reads or writes files, and scan those files. So each time you read/write a file, you’ve got multiple AVs fighting over who gets to access the file to scan it, on top of whatever original process was trying to open the file (eg. Word for a document). At best this causes poor disk I/O performance. It can also cause deadlocks (two processes waiting on each other for file access).
AVs also scan processes running in memory. It’s possible the AVs will try to scan each other, and maybe fail because AVs tend to run with special OS privileges that make it inaccessible to other software, but that’s never been a problem in my experience.
Imagine you have a box that checks your body for all manner of plagues and pestilence. Now, inside this box is a copy of all those plagues and pestilences. And it checks by comparing everything around you to those copies it holds. If there’s a match, it flags that match and sticks it in a big bubble.
Now imagine you have two boxes. Each box detects that the other box contains all manner of plagues and pestilence. So each box sticks the other in a bubble. Now neither one works right.
When the computer starts, the antivirus software stands guard at the over everything, like a bouncer at a club. There’s only one place a bouncer can stand, and if you try to put two there, they will fight for control of the bouncer position, and don’t let anyone in or out until they settle their feud over it, and the club, being the computer, has to wait for all of this before the party an start.
In some cases, both bouncers knock each other out and the club shuts down completely.
Source:
15+ years IT, with a fondness for cyber security + a 4 year old at home
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