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.http://thundercloud.net:80/infoave/tutorials/email-scanning/index.htm
Quote 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. http://thundercloud.net:80/infoave/tutorials/email-scanning/index.htm
Basically the same old misinformation that is trotted out.
While I certainly agree that there is negligible value in having outbound mail scanned the best way to keep viruses out of the mail files (such as the Outlook Express DBX files) is to scan the inbound mail. It is not typically the mail scanning that corrupts the mail files it is the on demand scans trying to excise viruses from the mail files or simply quarantining the mail files after the virus has been allowed in.
Indeed, Microsoft (the developers of Outlook Express) went to the trouble of writing a plugin interface in Outlook especially to facilitate the scanning of emails.
Many users these days will be happy to rely on the antivirus scans of email performed by the email services they use (notice that nobody tells the email services they should not use antivirus software to scan emails). Others want the added assurance of scanning their email as it arrives at their system.