Why You Don't Need To Run Manual Antivirus Scans

 

Do you regularly open your Antivirus Software and run scans? Microsoft Security Essentials and other antivirus programs believe it is necessary, warning you that your computer may be at risk if you haven't done it in a while.

In reality, these manual scans are not all that they seem. You can usually ignore your antivirus and it will do its work in the background without your help, alerting you only when it encounters a problem.

Why manual virus scans are unnecessary

Your antivirus always runs in the background. It monitors the processes running on your system, ensuring that no malicious processes are running. Whenever you download a new file or open a program, your antivirus quickly intervenes, examines the file, and compares it to viruses before allowing it to run. If you download a virus, your antivirus will notice it without the need to scan anything. For example, try downloading the EICAR test file - your antivirus will spring into action and take care of the file without the need for manual scans.

This feature is generally known as background scanning, real-time protection, resident protection, on-demand scanning, or something like that.

In other words, you don't need to run manual scans because your antivirus has already checked all files for malware as it arrives. You are also aware of all the software that is running on your system. Your antivirus program doesn't need you to click a button; it's already doing the job.

Anyway, your antivirus probably already runs its own manual scans. Antiviruses generally run background system scans once a week without interrupting you.

The Microsoft Security Essentials message is particularly silly. If MSE really believes that a manual scan is necessary, MSE has the ability to perform the scan in the background rather than scaring its users into clicking a button.

When to run manual scans

Manual scans are still useful in some cases, but you don't need to regularly open your antivirus program and start them:

• When you install an antivirus: When you install an antivirus for the first time, it will perform a full system scan right away. This allows antivirus to make sure that your computer is in a clean state and that there are no viruses lurking in unopened files on your hard drive. After performing this scan, your antivirus can trust that your system is safe. However, it will continue to scan files for malware when you open them.
• Check for inactive malware that was previously lost: Antiviruses use "definition files", which are updated periodically. These files basically contain a catalog of identified malware, and your antivirus compares the programs it runs against the catalog to see if they match. There may be an inactive virus lurking in an executable file deep within your hard drive that your antivirus missed during your first manual scan. If a virus definition has been added for that type, a malware, or antivirus " heuristic have been improved: it will only detect the inactive virus when you perform a manual scan. However, the virus will be detected if you try to run the file containing the virus or during a regularly scheduled full system scan.
• Get a second opinion: You should only have one Antivirus Software running at a time, as multiple background scanning antivirus programs can interfere with each other and cause problems on your computer. If you want to scan your computer with multiple antivirus programs, you will need to perform a manual scan with the second Antivirus Software instead of using its background scanning feature.

Why Background Protection Is Better Than Manual Scans

Optionally, you can disable background scanning in some antivirus programs and just run manual scans, but you shouldn't.

Think of your computer as your home and your anti-virus background scan protection like a security guard standing at your front door and searching everyone who tries to enter your home. A manual scan is the equivalent of a security guard looking for intruders in every inch of your home.

If you've already checked everyone who enters your home, you don't need to search every corner of your home for malicious people. In fact, it is much better to keep an eye on your door because in order to detect threats before they are allowed in, if you discover someone lurking in a dark corner of your home or PC, who knows what they have been doing in the time between when they were allowed in and when did you catch them. Once the software is running on your computer, it also has the potential to hide itself and prevent the Antivirus Software, and even the Windows Task Manager, from seeing that it is running. The software that does this is generally known as a root kit.

You want to catch the malware before the virus starts running (and infects) your computer, so stick with automatic background scanning instead of manual scans. Even if you scan every program you download manually before running it, you should use automatic scans for maximum protection against zero-day attacks. And other security threats.

Some security suites may delete cookies when you perform a manual scan, referring to them as "threats". This is a great way for the security suite to pretend that it is doing something valuable and justify its price. But you don't need a full security package, anyway, and you can always have your browser automatically clear cookies if you want to get rid of them.