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You need to be careful when using more than one anti-spyware tool. Used improperly more than one tool can cause conflicts.

I have Microsoft Antispyware in my windows XP computer but recently I read reviews in PC magazine and it recommended Spyware Doctor 3.5. I don't want to uninstall Microsoft Antispyware. Can I keep both of them running at the same time?

If one is good, two must be better, right? And three better still!

Well, yes and no. Depending on what you mean by "run", two can be better, or two can be a total mess.

Much like anti-virus programs, anti-spyware programs typically have two modes of operation:

  • Scan: in this mode, the utility examines memory and files on disk for traces of malware. Different anti-spyware programs look at different things, but typically it includes looking for known ".exe" or other files, entries in the system registry as well as other permanent traces of malware.

  • Monitor:: some anti-spyware utilities include components that are installed and keep running. These components monitor for changes that are indications of malicious behavior. Unexpected changes to the registry, for example, can be one such sign. Programs writing to certain files or certain locations, unless known to be good, can also often be signs of a spyware or other malicious activity. This monitoring process can stop, or at least alert on, suspicious behavior.

"More than one set of spyware monitoring components can cause conflicts."

Both modes are important components to managing spyware and keeping your system safe.

The problem with running more than one anti-spyware application is that second mode: monitoring. More than one set of spyware monitoring components can cause conflicts. They might coexist peacefully, but they might also prevent each other from working properly, or perhaps even declare each other as spyware.

However, running scans from more than one anti-spyware program can often be quite useful. The unfortunate reality is that while some anti-spyware programs are better than others, none of them catch absolutely everything. As a result, particularly when diagnosing a suspected problem, running the scan portion of an additional anti-spyware program or two can often help track down or eliminate the offending malware.

So the bottom line is quite simple: install or enable the real-time monitoring components of only one anti-spyware program at a time, but go ahead and use different anti-spyware scanners manually when tracking down a problem.

Article C2571 - February 26, 2006 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

May 26, 2008 5:58 PM

I read your article about running 2 anti-virus softwares and it was very helpful. So, I use AVG free download for my anti-virus protection and it includes anti-spyware. I also have Windows Defender running. But, I can't tell whether AVG anti-spyware is just scanning or if it is also monitoring. I know Defender is monitoring, so i wanted to disable the monitoring function of AVG, if I could. Do you know if AVG anti-spyware also monitors? Thanks.

December 1, 2008 7:51 AM

Hi. Is running Spyware Blaster alongside AVG's ant-spyware programs simultaneously a problem?
Joe from Barrie, ON

January 29, 2009 11:37 PM

Please tell me that using spyware doctor alone is sufficient or should i install AVG free also along with it?

Clem L.
June 18, 2010 4:54 PM

A couple of my friends use ad-aware and webroot together. Is that alright?

June 30, 2010 5:21 AM

yes i did have a nasty virus i did have eset he never pick up i did run avg still there i did run spyware same uhhuhuuhuh run malwarebytes same grrrrrrrr was ready too do a reformat so at the last resort did run spybot then bingo the virus gone then also could open task manager at last so only spyboat did fix my problem

Paul McGaw Jr.
March 29, 2011 9:17 PM

hi, I think the above person should go into the options of their AVG prgram to diable monitoring. It should have an option for monitoring if you can. I don't use AVG personally because it detects the lowest rate of viruses out of AVG, Avast, and Avira. I have avast. way better.

I completely agree with Leo's article. As I've used windows a while. Since I was a kid. 95 and 98 operating systems originally is what I started using. I have 7 now. Mon itoring means it runs in the background as said by Leo to see if something might cause harm or possibly be causing harm to your computer. Running more than one "monitoring software" can cause harm to your computer and slow it down. It's like more than one anti-virus or more than one forewall. Both slow and cause harm to computers when there is more than one.

I've personally never heard of spyware doctor. I use spywareblaster and superantispyware.

I quit using spybot as it started causing me problem son my computer and it ran way too slow. I also quit using ad-aware. I think the programs i use work way better.

Just my opinion.

October 13, 2011 3:25 PM

HI Leo I'm on your mailing list and i need to ask you a question. I'm running Comodo Pro & ESET NOD32 PRO on my computer would it be better for me just to run COMODO PRO by it self or is it all right to run them both at the same time?

Depends on how they're configured. More in this article already on the site: Can I run more than one anti-virus program? Anti-spyware program? Firewall? Should I?


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