We will explain why we stand by this and why many experts stand by this as well.
First, email is a just a file. A file like any other files. Email whether you read it or not, is stored on your hard drive. Malicious files attached to an email are located on your hard drive. To an anti-virus scanner it does not matter whether the offending file arrived by email, arrived by file-sharing,, or arrived by download. It is all the same to it. Any good up-to-date anti-virus will prevent you from opening a malicious worm or virus no matter how it arrived. Until and unless you click the attachment the virus or worm will not execute. And if you’re using Outlook Express, and you have kept it updated with the latest patches from windowsupdate it will not execute merely by looking at your email.
Our advice is sound. Email scanning might have been useful years ago, but not anymore. We’re not sure it ever was. Six or seven years ago one could wander the Internet and open emails rather freely. Viruses were rare and the number of people using anti-virus programs was small. With the Internet Boom of 1999 came an influx of millions of new people using the Internet and millions of new potential targets for those who have nothing better to do than to ruin other people’s fun. So worms, Trojans, and viruses became numerous, but still few used good anti-virus protection.
Email Scanning by any anti-virus is not recommended because the harm and delay that scanning can cause don’t justify the minimal (if any) benefits to be derived. One of the biggest problem caused by email virus scanners is corrupted Outlook Express DBX (data) files. If these files become corrupted, whatever mail you have stored in them will be unreadable. Email virus scanning is the number one cause of corrupted DBX files; and hence the biggest cause of unrecoverable email. Other problems are minor but they’re a nuisance: Aggravating delays in sending or receiving email being among the top nuisances.
Many others do agree with us on shutting off email scanning in your anti-virus program. The following article by Tom Koch, a Microsoft MVP explains it best. Mr. Koch details not only why you should turn off your email scanner but how Outlook Express works, as well as other interesting and little known Outlook Express facts. Here is an excerpt from his excellent article by Tom Koch:
“…When encountering the symptoms of DBX corruption, many people immediately fear that their computer is infected with a virus. As surprising and ironic as it may seem though, the most common cause of DBX corruption is not a virus, but rather anti-virus programs that are configured to scan incoming or outgoing e-mail. Even the most well-known anti-virus programs have exhibited this problem from time to time. To lessen the risk of such corruption you should disable the e-mail scanning module in your anti-virus program. This is usually easy to do by looking at the user-configurable options in the anti-virus program. It is not at all necessary to scan e-mail for viruses to protect your computer.
Now before you dismiss me as mad, let me explain why e-mail scanning is unnecessary. Almost every anti-virus program for Windows installs by default a system scan that runs in the background every time Windows starts. This scan is necessary to protect your computer. If you receive a virus in an e-mail attachment, the virus cannot do anything at all until you actually open the attachment. …”
The most important thing, and we cannot emphasize this strongly enough, is to use a good, reputable anti-virus program (AVAST and AVG are two good free ones) and keep it updated daily! An anti-virus program which is not updated is worse than none at all. It will return false-positives and ignore real threats. So, above all, keep your anti-virus program up-to-date. And NEVER open an attachment directly from your email. ALWAYS save it to your desktop (or another easily accessible folder) and scan it with your anti-virus program before opening it. Another thing we cannot emphasize enough: Keep your Microsoft Windows current.