We have released an Update to our free antivirus solution called "Microsoft Security Essentials".
The update is already live and is being pushed via Windows Update.
More information can be found in the following knowledge base article :
You are prompted to upgrade to the latest version of Microsoft Security Essentials (1.0.1963.0)http://support.microsoft.com/?kbid=975959
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I urge you to post your comments on this tool.