Microsoft's OneCare Live security subscription service has been updated with a feature to protect MSN Messenger users.

In the newest version, Windows OneCare will now run automatic scans of files received from the MSN Messenger IM client, a significant new feature designed to thwart the growing threat from instant message-borne malware.

Windows OneCare, formerly code-named A1, is a bundled service for virus scanning, firewall protection, data backup and PC cleanup tools. The plan is to add anti-spyware protection in future updates. It will be shipped as a fee-based, subscription service.