Running AVAST and Microsoft Security Essentials together.
So far no conflict. Any negatives to doing this you think?
Now I'm well aware that many Security Pros will STRONGLY advise against running two AV's because "they conflict... degrade performance...use vast resources...cause system instability... will slow your computer to a crawl....cause system conflicts and instability.... etc, etc---but very few of these respected & highly credentialed individuals offer little more than "because I'm an MVP & I say so" as a reason WHY all those things MAY (or may not?) occur. Then there's the UN-credentialed opinionated A**HOLES arguing on both sides with little more than "Because I'm smarter than you & I said so" arguments.
I spent a few hours today Googling the subject, and after reading through hundreds of topics on about a dozen sites I came across this post on the CNET forum which offers a very sound & easy to understand argument against running 2 AV's:
Reply # 29 by GoodTimeCharlie @ http://forums.cnet.com/7723-6132_102-309240.html
One needs to keep in mind the difference between products. Generally:
1. Firewall products monitor communications ports ... They must run at (are hooked into) the operating system level.
2. Anti-Virus products monitor a lot of things: File reads/writes, Software installs, E-Mail activity/attachments, Registry changes, Some network activity, Browser add-on install attempts, etc ... To provide 'real-time' protection they must also run at (hooked into) the operating system level, however they do not need to do so just to do an 'on-demand' scan of your system.
3. Anti-Spyware/Anti-Adware tend to look for attempts to access or execute known 'bad' program files, etc ... they are almost always run on-demand thus you may have multiple products installed as they will be self-contained in their own directory (not in the operating systems directory); however, some products offer real-time protection (IE: SpyBot S & D "TeaTimer") and the 'real-time' functions must be run at (hooked into) the OS also.
Each of these toolsets may 'modify' specific parts of the operating system by replacing the operating systems default program with their own (ie: inserting the 'hook') ... I say MAY because obviously a product designed to be manually fired up from an on-line site or the local C: drive usually does not modify the OS, but those products that 'run in the background' (ie: are started when you boot the PC) typically do hook into OS files.
4) If you install multiple products that are designed to 'stay within their world' (ie: a firewall product that does not include a built in anti-virus tool and an anti-virus tool that does not include a firewall) you will be OK; however,
5) if you install multiple products that: a) hook into the OS, and overlap in function (ie: 2 anti-virus checkers) they may overlay each others 'hooks' in the OS and you may not be OK.
6) keep in mind that every product installed will also modify the system registry (often used by the OS to find the program to be executed for a specific function), reconfiguring it to 'point' to that products executables when a certain condition occurs (ie: an 'open .exe file') ... thus the 'registry hooks' can also be reconfigured multiple times.
Additionally, should you install 2 anti-virus products, when you uninstall one of them, you may really be left with a mix of program files & registry entries that may trash your system effectively.
Note: due to anti-trust laws, etc., the Microsoft defender/firewall tools can 'exist' with other products; however, you should configure your system to have the Microsoft products disabled or you may run into problems and/or have horrible response issues.
I say this based upon working over 40 years as an IT specialist.
Goodtime Charlie, VA
I'd like to hear from you bleeper's on this subject