. I have always been under the impression that you could only run one antivirus program. but I thought you could run 2, or possible 3 antispyware programs with most antivirus programs.
Yes, using more than one anti-virus program is not advisable
The primary concern with doing so is due to conflicts that can arise
when they are running in real-time mode simultaneously and issues with Windows resource management. Even if one of them is disabled for use as a stand-alone scanner, it can affect the other and cause conflicts
. Anti-virus software components insert themselves into the operating systems core and using more than one can cause instability, crash your computer, slow performance and waste system resources
. When actively running in the background while connected to the Internet, they both may try to update their definition databases at the same time. As the programs compete for resources required to download the necessary files this often can result in sluggish system performance or unresponsive behavior.
Each anti-virus may interpret the activity of the other as suspicious behavior
and there is a greater chance of them alerting you to a "False Positive
". If one finds a virus or a suspicious file and then the other also finds the same, both programs will be competing over exclusive rights on dealing with that virus or suspicious file. Each anti-virus may attempt to remove the offending file and quarantine it at the same time resulting in a resource management issue as to which program gets permission to act first. If one anit-virus finds and quarantines the file before the other one does, then you encounter the problem of both wanting to scan each other's zipped or archived files and each reporting the other's quarantined contents. This can lead to a repetitive cycle of endless alerts that continually warn you that a threat has been found when that is not the case.
Anti-virus scanners use virus definitions to check for malware and these can include a fragment of the virus code which may be recognized by other anti-virus programs as the virus itself
. Because of this, many anti-virus vendors encrypt their definitions so that they do not trigger a false alarm when scanned by other security programs. Other vendors do not encrypt their definitions and they can trigger false alarms when detected by the resident anti-virus. Further, dual installation
is not always possible because most of the newer anti-virus programs will detect the presence of others and may insist they be removed prior to download and installation of another. If the installation does complete with another anti-virus already installed, you may encounter issues like system freezing, unresponsiveness
or similar symptoms while trying to use it.
To avoid these problems, use only one
anti-virus solution. Deciding which one to remove is your choice. Be aware that you may lose your subscription to that anti-virus program's virus definitions once you uninstall that software. Anti-virus vendors recommend that you install and run only one anti-virus program at a time
You can always supplement your anti-virus by performing an Online Virus Scan
In contrast, as a general rule
, using more than one anti-spyware program like Malwarebytes' Anti-Malware, SuperAntispyware, Windows Defender, Spybot S&D, Ad-Aware, Spyware Terminator, etc. will not conflict with each other or your anti-virus if using only one
of them for real-time protection and others as stand-alone scanners. In fact, doing so increases your protection coverage without
causing the same kind of conflicts or affecting the stability of your system that can occur when using more than one anti-virus. The overlap of protection from using different signature databases will aid in detection and removal of more threats when scanning your system for malware. However, competing tools may provide redundant alerts which can be annoying and/or confusing as a result of the overlap in protection.
If using multiple real-time resident shields (TeaTimer, Ad-Watch, MBAM Protection Module, Spyware Terminator Shields, etc.) together at the same time, there can be conflicts
when each application tries to compete for resources and exclusive rights to perform an action. They may identify the activity of each other as suspicious and produce alerts. Further, your anti-virus may detect suspicious activity while these programs are scanning (reading) files, especially if it uses a heuristic scanning
engine, regardless if they are running in real-time or on demand. The anti-virus may even detect as threats, any malware removed by these programs and placed into quarantined areas. This can lead to a repetitive cycle of endless alerts or false alarms that continually warn a threat has been found if the contents of the quarantine folder are not removed before beginning a new security scan. Generally these conflicts are more of an annoyance rather than the significant conflicts which occur when running two anti-virus programs in real time.
is no longer recommending
Spybot S&D or Ad-Aware due to poor testing results. See here
- (scroll down and read under Freeware Antispyware Products)
. Ad-Aware has even been placed into the Installers Hall of Shame
for bundling and pre-checking Google Chrome during the installation. Also read Lavasoft Turning to the Dark Side?
written by a former volunteer (now a MVP) who provided support for Ad-Aware but no longer uses the program.
As for Spybot S&D, most people don't understand how to use TeaTimer
and that feature can cause more problems than it's worth. TeaTimer monitors changes to certain critical keys in Windows registry
but does not indicate if the change is normal or a modification made by a malware infection. The user must have an understanding of the registry
and how TeaTimer works in order to make informed decisions
to allow or deny the detected changes. If you don't have understanding how a particular security tool works, then you probably should not be using it. Additionally, TeaTimer may conflict with other security tools which do a much better job of protecting your computer and in some cases it will even prevent disinfection
of malware by those tools.
More effective alternatives are Malwarebytes Anti-Malware
and SUPERAntiSpyware Free