Run two anti-virus programs simultaneously?

Question

Hello, I'm using two anti-virus programs simultaneously; AVG and Malwarebytes. They are fully up to date. I've been told by some that these, or indeed any, two AV programs will interfere with each other and cause risk. Is this really true? Surely Windows 10 would allow them to operate properly and independently. Thus, along with Windows Defender, such an arrangement would give very enhanced protection? if one program is not successful, one or both of the others will catch the bug? PS. I don't mind paying the extra money for I run a small business, and bugs, or ransomware, is something that I just could not cope with. Thanks.

Answer 1

The answer to this isn't as simple as it may seem and in fact has been made even more complex due to changes that Malwarebytes has made to their Anti-Malware product over the last few years.

The default advice that most will give is what you've already heard, that 2 AV programs will conflict and in terms of Windows this is true. The reason is that the Windows antivirus API (Application Programming Interface) calls that support calling an antivirus when a file is ether downloaded or written to disk were only originally designed to support a single antivirus program.

The reason for this is actually relatively simple to understand if you just think through the process required. When a file is written to the Windows filing system it is first held by Windows and the information required to identify, locate and scan the file is passed to the currently installed and registered AV application, which uses that information to automatically scan the file, returning the status of the file (malware or clean) to the operating system to either display or hand over control to whatever program was downloading or writing the file to disk.

The problem with 2 AV programs operating at the same time is that one will gain access to the file first, while if the second even gains control of the file, the potential for a conflict where both try to scan and/or potentially block the file if it's malware now exists, along with the probability that one (usually the first to gain control) may either delete or at least lock (e.g. quarantine) the file before the other can act. That's the best case result, since if instead the first performs its scan and the second happens to detect the file as malware as well, they both may attempt to remove or lock the file, causing one, the other or possibly both to fail to work properly generating either confusing multiple notifications or even file system errors.

The reason I mentioned that Malwrebytes Anti-Malware makes this answer more complex though is that they chose not to use the standard Windows API calls specifically so their application could coexist with a single standard 3rd-party AV app, either the built-in Windows Defender or another 3rd-party app that by default, will disable the Defender real-time protection when it's installed to avoid the potential conflicts mentioned above.

However, over the last 2 major revisions of Malwarebytes, they muddied the water even further by adding a partial set of AV scanning functions for what's known as the "Wildlist" of common virus detections. To avoid the potential conflicts this might create, Malwarebytes also added configuration settings that allow it to either register itself to take over as the default AV program or remain in the background running in parallel to the installed AV by using the alternate scanning methods they've always supported for the non-virus types of malicious programs they detect.

Now the complexity of this relatively simple set of modes of operation and configuration I've described should make one thing relatively obvious, there's actually nothing at all simple about all of this in practice. And that's the true problem, since even though their scanning system design is done differently, there's still potential for either misconfiguration by the PC user or simply that some change that Microsoft or another 3rd-party AV application vendor makes might unexpectedly cause a conflict, even though Malwarebytes takes pains to avoid this.

So though Malwarebytes tries to guarantee their Anti-Malware app can coexist and operate in tandem with a 3rd-party AV, we've occasionally seen reports of problems here likely caused by an undesired interaction between Malwarebytes and whatever other AV security application is operating on the machine.

Personally, despite Malwarebytes promise to make their Anti-Malware work in tandem with others, I've normally operated it in on demand mode only, with no real-time operation to insure it can't conflict with my preferred AV app Windows Defender. The only exception has been when Malwarebytes performs major application updates, which offers another free trial period that I'll sometimes allow to continue until the trial period runs out and it returns automatically to the free, on-demand scanning version.

Rob

Answer 2

Hi TramSpasm#2001& -

I'm Jerico T., one of the Independent Advisor and a fellow Windows 10 user like you. I understand that you're having some issues right now, let us sort things out.

It's not possible to run two antivirus programs simultaneously due to some reasons. Some users are doing it for they believe that it will make their system more protected. Running 2 antivirus on a single computer might lead to data/file corruption, each antivirus program’s will attempt to install parallel interceptors which might cause the entire computer system to crash.

I also found a post relevant to your concern, kindly click the link below.

https://answers.microsoft.com/en-us/protect/for...

Feel free to reach back if you need any further assistance.

Hope this help. Have a good day.

Thank you.

Jerico T.

Independent Advisor

Answer 3

Thankyou so much Rob and Jericho. I'll follow your example Rob and run Malwarebytes in demand mode only. So in this 'demand only' configuration, would it still be safe to use a Malwarebytes scanning schedule? Or would I have to disable that function as well, and only run scanning manually? I'm thinking that the chances of a bug arriving real time, and a Malwarebytes scheduled scan occurring together would be fairly small. Does that make sense?

I'd like to keep Malwarebytes if I can, even if in some lesser capability..

Answer 4

Suggest reading also through Choosing an Anti-Virus Program (which includes an security expert's view on AVG in this topic) as well as Supplementing your Anti-Virus Program with Anti-Malware Tools